{"kind": "plan", "major": "18", "item": {"slug": "cte-scan", "name": "CTE Scan", "name_zh": "CteScan", "category": "\u626b\u63cf", "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "aliases": ["CTE Scan", "CteScan", "T_CteScan"], "content_hash": "fd505c33d25413638c7173c8de831f6c4575c75674c6e87e29b5c210d266835f", "versions": {"10": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "76539aff4782b2c3ee3a3bf3cbff825324ba22bd726030a924b4f2ec682b9f0f", "archive_sha256": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, {"url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "dcf45a15db0b6fce8d77783138557f9fcb956b5c45dceac9ec734c2990f8cb97", "archive_sha256": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=10", "label": "EXPLAIN"}, {"url": "/docs/10/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/10/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=10", "label": "work_mem"}], "release": {"ref": "PostgreSQL 10.23 source archive", "label": "10.23", "major": "10", "channel": "historical", "revision": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9", "source_url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "line": 971, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:971", "sha256": "a785298532047cfeda969e78c3597a343dc1c56d61ba85830b0f16a02a14b5a1", "archive_sha256": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, {"url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "line": 262, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:262", "sha256": "cea76648bb38ae55f18f989768bee1a4ee025691ceea0f86bccb29dcdc166acc", "archive_sha256": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, {"url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "76539aff4782b2c3ee3a3bf3cbff825324ba22bd726030a924b4f2ec682b9f0f", "archive_sha256": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, {"url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "d562c321108844798cd234303fffb618f13d4ee3f3a5ac79bfd963b077e47c22", "archive_sha256": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, {"url": "https://ftp.postgresql.org/pub/source/v10.23/postgresql-10.23.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "dcf45a15db0b6fce8d77783138557f9fcb956b5c45dceac9ec734c2990f8cb97", "archive_sha256": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/10/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "10", "build_id": 63, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "04aacb3e491b4aeabbfc54a60ddedcc5fafcc469c0823a375c35a83ec42575c6", "fragment_sha256": "82af09517c7be979ac518f6bede1cb5e44f328ebf207cc6b25aa2313dff5f7a6", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:62997ea80516ad012fbf6359de33f3b016b54c47e2df76e75606116b4baaf8e5", "translated_from_revision": null}, "body_sha256": "6468a920e7183cb832be1b7d16ed19ad7618426931ba93e8334203bd245a41e2", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "10", "text_hash": "cada6d89fa45f90028fe4722a35cd4b736cd6bd518637eff3205dd4d97203725", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/10/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "10", "build_id": 63, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "04aacb3e491b4aeabbfc54a60ddedcc5fafcc469c0823a375c35a83ec42575c6", "fragment_sha256": "82af09517c7be979ac518f6bede1cb5e44f328ebf207cc6b25aa2313dff5f7a6", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:62997ea80516ad012fbf6359de33f3b016b54c47e2df76e75606116b4baaf8e5", "translated_from_revision": null}, "body_sha256": "6468a920e7183cb832be1b7d16ed19ad7618426931ba93e8334203bd245a41e2", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p> <span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"xref\" href=\"/zh/docs/10/sql-explain.html\"><span class=\"refentrytitle\">EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/10/performance-tips.html#USING-EXPLAIN\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "10", "link_map": {"/zh/docs/10/sql-explain.html": "/docs/10/sql-explain.html", "/zh/docs/10/performance-tips.html#USING-EXPLAIN": "/docs/10/performance-tips.html#USING-EXPLAIN"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p> <span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/10/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/10/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "190bcd388ead790b6100d427d9778ee32058e20e5dcc75a98623b333989365aa", "content_hash": "cada6d89fa45f90028fe4722a35cd4b736cd6bd518637eff3205dd4d97203725", "source_database": "center", "source_revision": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/10/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/10/facts/0/label": "Core node tag", "/versions/10/facts/1/label": "Structured EXPLAIN Node Type", "/versions/10/facts/2/label": "Inputs", "/versions/10/facts/2/value": "A CTE plan and shared tuplestore", "/versions/10/facts/3/label": "Output", "/versions/10/facts/3/value": "CTE result tuples", "/versions/10/facts/4/label": "Executor initializer", "/versions/10/facts/5/label": "Memory mechanism", "/versions/10/tables/0/title": "EXPLAIN labels in this source build", "/versions/10/related/1/label": "Using EXPLAIN", "/versions/10/related/2/label": "Parallel plans", "/versions/10/sections/0/title": "EXPLAIN names and attributes", "/versions/10/sections/1/title": "Memory and temporary storage", "/versions/10/sections/2/title": "Parallel execution and instrumentation", "/versions/10/sections/3/title": "Executor implementation notes", "/versions/10/sections/4/title": "EXPLAIN identity in core source", "/versions/10/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/10/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/10/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/10/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/10/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/10/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/10/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/10/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/10/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/10/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/10/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/10/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/10/tables/0/columns/0/label": "Text-format label", "/versions/10/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "9c2f6929b6928af410b5a43a56525f2be1db7a6e2e5cda97e705bff21ba36713", "canonical_center_text_hash": "cada6d89fa45f90028fe4722a35cd4b736cd6bd518637eff3205dd4d97203725"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p> <span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/10/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/10/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "11": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "73f6fbda36cb2584110cfcf80fbe746dfbf7621bc0924697a8d24d64e859eb38", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, {"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "2891704a2b38e4f4c52cce4604f1cad8b83781217697c4cddd6d3d99ddc14fce", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=11", "label": "EXPLAIN"}, {"url": "/docs/11/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/11/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=11", "label": "work_mem"}], "release": {"ref": "PostgreSQL 11.22 source archive", "label": "11.22", "major": "11", "channel": "historical", "revision": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0", "source_url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "line": 1096, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1096", "sha256": "9df8400c1a4377179572ceb916d6020fca4e2760f74bf416d77ed97476523bbd", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, {"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "line": 262, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:262", "sha256": "95ef4d4a5df4c29f14af9763fae2c530449bdacdf3853d9ff297adf1fed6153b", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, {"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", 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"/zh/docs/11/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "11", "build_id": 64, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "617a30102327f61276ba77fb034f4bf1bbb677d91d4eb5507dc14d740e6394c9", "fragment_sha256": "a7b71780192bea8bfc169883aae459f6d32a71fe928f60388479827c9c8b54bc", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:ef5c7bc074acae9795db16e6b7482aea3b222bd4bcce0f76831332b97a21e8a1", "translated_from_revision": null}, "body_sha256": "429f0e6e1c28327e7aacf7251c310e56ca080ae3fcc77bd0aba1f1042871acf9", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "11", "text_hash": "e697c48589425b19a6b57a5c793870bc9b007712acd6448df67cba8194397dd2", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/11/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "11", "build_id": 64, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "617a30102327f61276ba77fb034f4bf1bbb677d91d4eb5507dc14d740e6394c9", "fragment_sha256": "a7b71780192bea8bfc169883aae459f6d32a71fe928f60388479827c9c8b54bc", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:ef5c7bc074acae9795db16e6b7482aea3b222bd4bcce0f76831332b97a21e8a1", "translated_from_revision": null}, "body_sha256": "429f0e6e1c28327e7aacf7251c310e56ca080ae3fcc77bd0aba1f1042871acf9", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"xref\" href=\"/zh/docs/11/sql-explain.html\"><span class=\"refentrytitle\">EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/11/performance-tips.html#USING-EXPLAIN\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "11", "link_map": {"/zh/docs/11/sql-explain.html": "/docs/11/sql-explain.html", "/zh/docs/11/performance-tips.html#USING-EXPLAIN": "/docs/11/performance-tips.html#USING-EXPLAIN"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/11/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/11/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "bc469e87a2bffb1d5facb90703e86b857492cccb451a36c1525005f1d843f732", "content_hash": "e697c48589425b19a6b57a5c793870bc9b007712acd6448df67cba8194397dd2", "source_database": "center", "source_revision": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/11/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/11/facts/0/label": "Core node tag", "/versions/11/facts/1/label": "Structured EXPLAIN Node Type", "/versions/11/facts/2/label": "Inputs", "/versions/11/facts/2/value": "A CTE plan and shared tuplestore", "/versions/11/facts/3/label": "Output", "/versions/11/facts/3/value": "CTE result tuples", "/versions/11/facts/4/label": "Executor initializer", "/versions/11/facts/5/label": "Memory mechanism", "/versions/11/tables/0/title": "EXPLAIN labels in this source build", "/versions/11/related/1/label": "Using EXPLAIN", "/versions/11/related/2/label": "Parallel plans", "/versions/11/sections/0/title": "EXPLAIN names and attributes", "/versions/11/sections/1/title": "Memory and temporary storage", "/versions/11/sections/2/title": "Parallel execution and instrumentation", "/versions/11/sections/3/title": "Executor implementation notes", "/versions/11/sections/4/title": "EXPLAIN identity in core source", "/versions/11/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/11/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/11/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/11/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/11/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/11/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/11/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/11/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/11/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/11/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/11/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/11/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/11/tables/0/columns/0/label": "Text-format label", "/versions/11/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "530dc69c6bad7794c312ebcf8e9b3486e1c0092476615ef21e5fb362c935ce57", "canonical_center_text_hash": "e697c48589425b19a6b57a5c793870bc9b007712acd6448df67cba8194397dd2"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/11/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/11/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "12": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "b1c4e77ae9019fe1231099661b21bbb56a6dcade05f21a266786494fc86af1ab", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "44cccd98d659272f5c8f3ff6adffb1f6cc911acd13a3cfafc74cc7841318f929", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=12", "label": "EXPLAIN"}, {"url": "/docs/12/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/12/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=12", "label": "work_mem"}], "release": {"ref": "PostgreSQL 12.22 source archive", "label": "12.22", "major": "12", "channel": "historical", "revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b", "source_url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "line": 1167, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1167", "sha256": "d02ea84fdaa201de5d9360645a9f24bfbd2c31f7d45a639e09560ac0e6b6471d", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "line": 262, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:262", "sha256": "311b17379fe54e3f342fe5ad41c43afbdfa1b844978db2bb2eb22b82520d3256", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", 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"/zh/docs/12/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "12", "build_id": 65, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "773efea8d76bcea57eb449ceb506a51025a4125ceaa9b765a1039e558f5cfe98", "fragment_sha256": "5563b70cc4f15175ea74a689b7145d309617eefbe2ea27e4fce422e01369eff6", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:86d2ff781f93e1de17122ebc514d5e64fcb63fed15941f496d7e146c6dcc7a49", "translated_from_revision": null}, "body_sha256": "311cb4e69497634c1288073199ff9b93ea6e5c57032225036f40ffcde5bab5e1", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "12", "text_hash": "968ac712863c33b88367454afb8205a60a428ead14cc3a86d4e967cc9c45b198", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/12/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "12", "build_id": 65, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "773efea8d76bcea57eb449ceb506a51025a4125ceaa9b765a1039e558f5cfe98", "fragment_sha256": "5563b70cc4f15175ea74a689b7145d309617eefbe2ea27e4fce422e01369eff6", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:86d2ff781f93e1de17122ebc514d5e64fcb63fed15941f496d7e146c6dcc7a49", "translated_from_revision": null}, "body_sha256": "311cb4e69497634c1288073199ff9b93ea6e5c57032225036f40ffcde5bab5e1", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"xref\" href=\"/zh/docs/12/sql-explain.html\"><span class=\"refentrytitle\">EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/12/performance-tips.html#USING-EXPLAIN\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "12", "link_map": {"/zh/docs/12/sql-explain.html": "/docs/12/sql-explain.html", "/zh/docs/12/performance-tips.html#USING-EXPLAIN": "/docs/12/performance-tips.html#USING-EXPLAIN"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/12/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/12/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "8c4161894a9209f847d7e47c4c13a3340f67c95fc24e71cd2928fba4dd615e56", "content_hash": "968ac712863c33b88367454afb8205a60a428ead14cc3a86d4e967cc9c45b198", "source_database": "center", "source_revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/12/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/12/facts/0/label": "Core node tag", "/versions/12/facts/1/label": "Structured EXPLAIN Node Type", "/versions/12/facts/2/label": "Inputs", "/versions/12/facts/2/value": "A CTE plan and shared tuplestore", "/versions/12/facts/3/label": "Output", "/versions/12/facts/3/value": "CTE result tuples", "/versions/12/facts/4/label": "Executor initializer", "/versions/12/facts/5/label": "Memory mechanism", "/versions/12/tables/0/title": "EXPLAIN labels in this source build", "/versions/12/related/1/label": "Using EXPLAIN", "/versions/12/related/2/label": "Parallel plans", "/versions/12/sections/0/title": "EXPLAIN names and attributes", "/versions/12/sections/1/title": "Memory and temporary storage", "/versions/12/sections/2/title": "Parallel execution and instrumentation", "/versions/12/sections/3/title": "Executor implementation notes", "/versions/12/sections/4/title": "EXPLAIN identity in core source", "/versions/12/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/12/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/12/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/12/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/12/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/12/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/12/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/12/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/12/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/12/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/12/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/12/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/12/tables/0/columns/0/label": "Text-format label", "/versions/12/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "66ad3da228dcd6afa8b3bc647ae504216f1347248887dc07b7008f803f363bb1", "canonical_center_text_hash": "968ac712863c33b88367454afb8205a60a428ead14cc3a86d4e967cc9c45b198"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/12/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/12/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "13": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "85c31c9845b3947381b9bbb91678b12390efaeea48ebda730f7b1e5e0783411a", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "4cba6490949d7dd9338b8499fcbb489e84cfd6cda9b98599512eb40bfbde6f9d", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=13", "label": "EXPLAIN"}, {"url": "/docs/13/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/13/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=13", "label": "work_mem"}], "release": {"ref": "PostgreSQL 13.23 source archive", "label": "13.23", "major": "13", "channel": "historical", "revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6", "source_url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "line": 1225, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1225", "sha256": "541713e0e7f1c9cc352c2b6028964d440c19d2678a4463000094c24a88c1e730", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "line": 262, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:262", "sha256": "d085ee99acfa00587e6ade3a1d9f8108a0566beedbbee3f54a50c9fc0cc2e875", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", 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"/zh/docs/13/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "13", "build_id": 66, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "d7400476f3cf658423dd2d2f64b6b6b0e53d8fdc8692b9e93a05587095d469e1", "fragment_sha256": "9385d1b095126378694216a1f9cb95d249ccc7fab5ffa3f65cf08679fe2b14c3", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:a13a825c39f0268ef1cfe9137e283e38d0da73b2d7894f0733c7b26372a4f6a4", "translated_from_revision": null}, "body_sha256": "86d97c4bd4b9d738c5510cbeb99e2f87c65f9ba8a2296230a7007b3bc9293718", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "13", "text_hash": "30c1a8e20782077e8031c313146ec131c4074d1add82fd3024f017de86c70738", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/13/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "13", "build_id": 66, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "d7400476f3cf658423dd2d2f64b6b6b0e53d8fdc8692b9e93a05587095d469e1", "fragment_sha256": "9385d1b095126378694216a1f9cb95d249ccc7fab5ffa3f65cf08679fe2b14c3", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "snapshot:sha256:a13a825c39f0268ef1cfe9137e283e38d0da73b2d7894f0733c7b26372a4f6a4", "translated_from_revision": null}, "body_sha256": "86d97c4bd4b9d738c5510cbeb99e2f87c65f9ba8a2296230a7007b3bc9293718", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"xref\" href=\"/zh/docs/13/sql-explain.html\"><span class=\"refentrytitle\">EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/13/performance-tips.html#USING-EXPLAIN\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "13", "link_map": {"/zh/docs/13/sql-explain.html": "/docs/13/sql-explain.html", "/zh/docs/13/performance-tips.html#USING-EXPLAIN": "/docs/13/performance-tips.html#USING-EXPLAIN"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/13/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/13/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "5c465253f81fc32a5755f7c8738754a644cbdb6743a20499ec632a6ce9772ff5", "content_hash": "30c1a8e20782077e8031c313146ec131c4074d1add82fd3024f017de86c70738", "source_database": "center", "source_revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/13/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/13/facts/0/label": "Core node tag", "/versions/13/facts/1/label": "Structured EXPLAIN Node Type", "/versions/13/facts/2/label": "Inputs", "/versions/13/facts/2/value": "A CTE plan and shared tuplestore", "/versions/13/facts/3/label": "Output", "/versions/13/facts/3/value": "CTE result tuples", "/versions/13/facts/4/label": "Executor initializer", "/versions/13/facts/5/label": "Memory mechanism", "/versions/13/tables/0/title": "EXPLAIN labels in this source build", "/versions/13/related/1/label": "Using EXPLAIN", "/versions/13/related/2/label": "Parallel plans", "/versions/13/sections/0/title": "EXPLAIN names and attributes", "/versions/13/sections/1/title": "Memory and temporary storage", "/versions/13/sections/2/title": "Parallel execution and instrumentation", "/versions/13/sections/3/title": "Executor implementation notes", "/versions/13/sections/4/title": "EXPLAIN identity in core source", "/versions/13/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/13/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/13/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/13/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/13/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/13/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/13/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/13/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/13/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/13/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/13/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/13/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/13/tables/0/columns/0/label": "Text-format label", "/versions/13/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "a0f2816a423583f83de75b94029816d1d0895b97086af05090604ce9a40c0c39", "canonical_center_text_hash": "30c1a8e20782077e8031c313146ec131c4074d1add82fd3024f017de86c70738"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/13/sql-explain.html\" rel=\"nofollow\"><span>EXPLAIN</span></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/13/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "14": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "da1f7fed71edfdb58ca0f1be133173ec3253d22135916cf3ff61d1fdc60cfb77", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "833cff27e0a2c863b9e897cd3bf4127df1b3e3a9b976694f3323a1c1a466d9b2", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=14", "label": "EXPLAIN"}, {"url": "/docs/14/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/14/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=14", "label": "work_mem"}], "release": {"ref": "PostgreSQL 14.24 source archive", "label": "14.24", "major": "14", "channel": "stable", "revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897", "source_url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "line": 1264, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1264", "sha256": "e091be4e2a083b8dea39ccd09beedede22c1716ef974da66c214a44f48be8c41", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "line": 269, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:269", "sha256": "72da1c5ad457f1d92a39ab73531701794df858419e3b89d6e6cb7079634e68fa", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", 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"/zh/docs/14/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "14", "build_id": 99, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "62cadce9a200c7891b3bbf04fc22c8dc17b4525aec0d020a074310592666f6d4", "fragment_sha256": "44f0e04fca33c2837461b83f68b9337a6abf37b979c0097630f9ab322fb3c567", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:87e6aa4fd6e1ec85c5f4a6de4f5647cfd9e5de734ca2c266d32b6d6192c662ef", "translated_from_revision": null}, "body_sha256": "f4a7dd18cf1d31834a4fc61a309971696d72b942483044e4945407d73ee4f84b", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "14", "text_hash": "9b8d9605f2e360553346813f3cc3ce18403c153094e352306396fde072dadf91", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/14/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "14", "build_id": 99, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "62cadce9a200c7891b3bbf04fc22c8dc17b4525aec0d020a074310592666f6d4", "fragment_sha256": "44f0e04fca33c2837461b83f68b9337a6abf37b979c0097630f9ab322fb3c567", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:87e6aa4fd6e1ec85c5f4a6de4f5647cfd9e5de734ca2c266d32b6d6192c662ef", "translated_from_revision": null}, "body_sha256": "f4a7dd18cf1d31834a4fc61a309971696d72b942483044e4945407d73ee4f84b", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/14/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/14/performance-tips.html#USING-EXPLAIN\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "14", "link_map": {"/zh/docs/14/sql-explain.html": "/docs/14/sql-explain.html", "/zh/docs/14/performance-tips.html#USING-EXPLAIN": "/docs/14/performance-tips.html#USING-EXPLAIN"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/14/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/14/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "0a9c2a0784719e02479a32d6c295c309f16ca3eddab938c8eddd0e3fe43fca9d", "content_hash": "9b8d9605f2e360553346813f3cc3ce18403c153094e352306396fde072dadf91", "source_database": "center", "source_revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/14/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/14/facts/0/label": "Core node tag", "/versions/14/facts/1/label": "Structured EXPLAIN Node Type", "/versions/14/facts/2/label": "Inputs", "/versions/14/facts/2/value": "A CTE plan and shared tuplestore", "/versions/14/facts/3/label": "Output", "/versions/14/facts/3/value": "CTE result tuples", "/versions/14/facts/4/label": "Executor initializer", "/versions/14/facts/5/label": "Memory mechanism", "/versions/14/tables/0/title": "EXPLAIN labels in this source build", "/versions/14/related/1/label": "Using EXPLAIN", "/versions/14/related/2/label": "Parallel plans", "/versions/14/sections/0/title": "EXPLAIN names and attributes", "/versions/14/sections/1/title": "Memory and temporary storage", "/versions/14/sections/2/title": "Parallel execution and instrumentation", "/versions/14/sections/3/title": "Executor implementation notes", "/versions/14/sections/4/title": "EXPLAIN identity in core source", "/versions/14/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/14/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/14/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/14/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/14/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/14/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/14/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/14/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/14/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/14/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/14/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/14/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/14/tables/0/columns/0/label": "Text-format label", "/versions/14/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "2a176cf9851289c40b8f0f6e85c0403a5860609816ca972f692d69b2377fcb66", "canonical_center_text_hash": "9b8d9605f2e360553346813f3cc3ce18403c153094e352306396fde072dadf91"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/14/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/14/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "15": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "585e8d9566e2fa33c4339750f285bbff38815a4f03ddf8c5558c57447cc8aca4", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "37be0ffb18c97558ea6fe6e1e0072564026b231edb9edf0a29faf27f13827aab", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=15", "label": "EXPLAIN"}, {"url": "/docs/15/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/15/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=15", "label": "work_mem"}], "release": {"ref": "PostgreSQL 15.19 source archive", "label": "15.19", "major": "15", "channel": "stable", "revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89", "source_url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "line": 1267, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1267", "sha256": "bb3b442d0f1b098aa8707335250102f027a596cd94117308bd16d1d36b258f5c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "line": 269, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:269", "sha256": "19836c50a272741a4eac653541e655437c2e00710a541e5348d6a277d0669d7c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", 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"/zh/docs/15/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "15", "build_id": 101, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "d842974e11d60f39bee19269d456c1cf6a01bc6c2c3ac27d8d1e7966ef5f46b9", "fragment_sha256": "16561716621b0c2403eaa78c0cd62211754eaec8fd5716f685f693e1deb3a07b", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:6bce1a2df9170cb1146a1411c5547190856638221a6539e618ee1016c9f493ad", "translated_from_revision": null}, "body_sha256": "8d856373aaa78cfe06eb1321fd5205dc4c0a39c6705b8893cf4065a4cdfeaf2e", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "15", "text_hash": "cb8e1a2f96c2b35dcf2715bd70a982f4d7d2a860d6923ac35afb1634c831a9dc", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/15/performance-tips.html#USING-EXPLAIN", "anchor": "USING-EXPLAIN", "locale": "zh-Hans", "version": "15", "build_id": 101, "page_key": "performance-tips.html", "extraction": "concept-introduction", "source_hash": "d842974e11d60f39bee19269d456c1cf6a01bc6c2c3ac27d8d1e7966ef5f46b9", "fragment_sha256": "16561716621b0c2403eaa78c0cd62211754eaec8fd5716f685f693e1deb3a07b", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:6bce1a2df9170cb1146a1411c5547190856638221a6539e618ee1016c9f493ad", "translated_from_revision": null}, "body_sha256": "8d856373aaa78cfe06eb1321fd5205dc4c0a39c6705b8893cf4065a4cdfeaf2e", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/15/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/15/performance-tips.html#USING-EXPLAIN\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "15", "link_map": {"/zh/docs/15/sql-explain.html": "/docs/15/sql-explain.html", "/zh/docs/15/performance-tips.html#USING-EXPLAIN": "/docs/15/performance-tips.html#USING-EXPLAIN"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/15/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/15/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "553a7a5435a3b6b3329a5c0b6e56184345c5e7b49f9bee1d68dddaa0e1212661", "content_hash": "cb8e1a2f96c2b35dcf2715bd70a982f4d7d2a860d6923ac35afb1634c831a9dc", "source_database": "center", "source_revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/15/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/15/facts/0/label": "Core node tag", "/versions/15/facts/1/label": "Structured EXPLAIN Node Type", "/versions/15/facts/2/label": "Inputs", "/versions/15/facts/2/value": "A CTE plan and shared tuplestore", "/versions/15/facts/3/label": "Output", "/versions/15/facts/3/value": "CTE result tuples", "/versions/15/facts/4/label": "Executor initializer", "/versions/15/facts/5/label": "Memory mechanism", "/versions/15/tables/0/title": "EXPLAIN labels in this source build", "/versions/15/related/1/label": "Using EXPLAIN", "/versions/15/related/2/label": "Parallel plans", "/versions/15/sections/0/title": "EXPLAIN names and attributes", "/versions/15/sections/1/title": "Memory and temporary storage", "/versions/15/sections/2/title": "Parallel execution and instrumentation", "/versions/15/sections/3/title": "Executor implementation notes", "/versions/15/sections/4/title": "EXPLAIN identity in core source", "/versions/15/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/15/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/15/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/15/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/15/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/15/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/15/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/15/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/15/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/15/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/15/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/15/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/15/tables/0/columns/0/label": "Text-format label", "/versions/15/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "66d342d9d7a5b4b6b051eef6b21f4269192be4c7e4aac2aa8ec8afa23cdf5e6a", "canonical_center_text_hash": "cb8e1a2f96c2b35dcf2715bd70a982f4d7d2a860d6923ac35afb1634c831a9dc"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/15/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/15/performance-tips.html#USING-EXPLAIN\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "16": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "7dbbb7d771920642c931327e7a14362ed0cea40b688d3011d522ac2ce0a6bb94", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "a990669858f1847ac83b5e1e65cf5515fe05ea0ad45ff64dd9347ba4f2110e62", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=16", "label": "EXPLAIN"}, {"url": "/docs/16/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/16/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=16", "label": "work_mem"}], "release": {"ref": "PostgreSQL 16.15 source archive", "label": "16.15", "major": "16", "channel": "stable", "revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed", "source_url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "line": 1300, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1300", "sha256": "8e017f0116dbea471339b40c37a667cc9f95039e7e0329c783e5e8ce194de7e1", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "line": 269, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:269", "sha256": "e48c08e555f8cb4e4bb43df516c4b8906ce9bc374b2a745d98a1fc8c22cc5099", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", 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"locale": "zh-Hans", "version": "16", "build_id": 103, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "394de9d6895c7909a1a823408b8c980c5415db8ca3c212e23d6e7e9b6e01c6cc", "fragment_sha256": "8a4cc7ad0a2c8ca5894434db8a1fca93a69bfb200ac510843c26d7bd42a12d58", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:80579a071736780f9c4022bb5148e1fb1256f1a33591306af67816e9e9bf3a9b", "translated_from_revision": null}, "body_sha256": "f36a649fb84607a8ae708fd6599459b7055d7653b6d55db3bf8978eec34c5133", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "16", "text_hash": "d8652b8fcc6cf235b6e4cfcff8372df04ad70dd63265baea048ce66f165e95c2", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/16/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "16", "build_id": 103, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "394de9d6895c7909a1a823408b8c980c5415db8ca3c212e23d6e7e9b6e01c6cc", "fragment_sha256": "8a4cc7ad0a2c8ca5894434db8a1fca93a69bfb200ac510843c26d7bd42a12d58", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:80579a071736780f9c4022bb5148e1fb1256f1a33591306af67816e9e9bf3a9b", "translated_from_revision": null}, "body_sha256": "f36a649fb84607a8ae708fd6599459b7055d7653b6d55db3bf8978eec34c5133", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/16/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/16/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "16", "link_map": {"/zh/docs/16/sql-explain.html": "/docs/16/sql-explain.html", "/zh/docs/16/using-explain.html": "/docs/16/using-explain.html"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/16/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/16/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "82b375830669a59ee64f4085c537e3fb255fbf7dd466631ad3fd85ea325201e5", "content_hash": "d8652b8fcc6cf235b6e4cfcff8372df04ad70dd63265baea048ce66f165e95c2", "source_database": "center", "source_revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/16/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/16/facts/0/label": "Core node tag", "/versions/16/facts/1/label": "Structured EXPLAIN Node Type", "/versions/16/facts/2/label": "Inputs", "/versions/16/facts/2/value": "A CTE plan and shared tuplestore", "/versions/16/facts/3/label": "Output", "/versions/16/facts/3/value": "CTE result tuples", "/versions/16/facts/4/label": "Executor initializer", "/versions/16/facts/5/label": "Memory mechanism", "/versions/16/tables/0/title": "EXPLAIN labels in this source build", "/versions/16/related/1/label": "Using EXPLAIN", "/versions/16/related/2/label": "Parallel plans", "/versions/16/sections/0/title": "EXPLAIN names and attributes", "/versions/16/sections/1/title": "Memory and temporary storage", "/versions/16/sections/2/title": "Parallel execution and instrumentation", "/versions/16/sections/3/title": "Executor implementation notes", "/versions/16/sections/4/title": "EXPLAIN identity in core source", "/versions/16/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/16/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/16/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/16/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/16/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/16/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/16/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/16/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/16/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/16/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/16/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/16/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/16/tables/0/columns/0/label": "Text-format label", "/versions/16/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "8af63a780b7fdebcea8a79e0a912d5118f91ea334d0bbfce45607499dad34500", "canonical_center_text_hash": "d8652b8fcc6cf235b6e4cfcff8372df04ad70dd63265baea048ce66f165e95c2"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/16/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f 9.3 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/16/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "17": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "19d5e7416c4d57b92f9e0c5c706079b00106a922f26be3f6c40346f5cc5a09b3", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "0d4316ed2d09288c2e3be15be1ce01b88622354bcd571ac7ebc45aa9319b90e7", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=17", "label": "EXPLAIN"}, {"url": "/docs/17/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/17/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=17", "label": "work_mem"}], "release": {"ref": "PostgreSQL 17.11 source archive", "label": "17.11", "major": "17", "channel": "stable", "revision": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979", "source_url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "line": 1489, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1489", "sha256": "741251b1a3b6d269a52a673d42eb63b02e13a5872db7b359b137086ab21b63c8", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "line": 269, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:269", "sha256": "a77576e158b94cb01fa8c5174ba133004eabdd727660323f8afc66c8d2e757b8", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "19d5e7416c4d57b92f9e0c5c706079b00106a922f26be3f6c40346f5cc5a09b3", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "d390dd69e2d3f5085beb42b33e46ff0676a2959b916a12b82118a7e545f8e562", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "0d4316ed2d09288c2e3be15be1ce01b88622354bcd571ac7ebc45aa9319b90e7", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/17/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "17", "build_id": 105, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "b1252952c6d796f5e38c223b74ff667f2d19d677dcf85fe5269b782b830e5013", "fragment_sha256": "8f5243c368dfae57e826af49b7461d37d7f4d97207bd5f540aebe6b10a61f883", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:7340767258d21c21b36f373f1fff6bab2be18e0daca13a865129db6105c09efd", "translated_from_revision": null}, "body_sha256": "b477e1ecd0c4336cecc7defd87f4fd6b682d2ff0cf148947e6f96f16e45bda34", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "17", "text_hash": "ff3bae482400ee83dd0789eeae5dfc214589c3c9234e60cbeabc21fb1d6e204c", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/17/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "17", "build_id": 105, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "b1252952c6d796f5e38c223b74ff667f2d19d677dcf85fe5269b782b830e5013", "fragment_sha256": "8f5243c368dfae57e826af49b7461d37d7f4d97207bd5f540aebe6b10a61f883", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:7340767258d21c21b36f373f1fff6bab2be18e0daca13a865129db6105c09efd", "translated_from_revision": null}, "body_sha256": "b477e1ecd0c4336cecc7defd87f4fd6b682d2ff0cf148947e6f96f16e45bda34", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/17/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v17 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/17/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "17", "link_map": {"/zh/docs/17/sql-explain.html": "/docs/17/sql-explain.html", "/zh/docs/17/using-explain.html": "/docs/17/using-explain.html"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/17/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v17 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/17/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "647f3d02137db61bd73a671fd3f7f2bf5d01bf51330c1069899efb330704176e", "content_hash": "ff3bae482400ee83dd0789eeae5dfc214589c3c9234e60cbeabc21fb1d6e204c", "source_database": "center", "source_revision": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/17/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/17/facts/0/label": "Core node tag", "/versions/17/facts/1/label": "Structured EXPLAIN Node Type", "/versions/17/facts/2/label": "Inputs", "/versions/17/facts/2/value": "A CTE plan and shared tuplestore", "/versions/17/facts/3/label": "Output", "/versions/17/facts/3/value": "CTE result tuples", "/versions/17/facts/4/label": "Executor initializer", "/versions/17/facts/5/label": "Memory mechanism", "/versions/17/tables/0/title": "EXPLAIN labels in this source build", "/versions/17/related/1/label": "Using EXPLAIN", "/versions/17/related/2/label": "Parallel plans", "/versions/17/sections/0/title": "EXPLAIN names and attributes", "/versions/17/sections/1/title": "Memory and temporary storage", "/versions/17/sections/2/title": "Parallel execution and instrumentation", "/versions/17/sections/3/title": "Executor implementation notes", "/versions/17/sections/4/title": "EXPLAIN identity in core source", "/versions/17/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/17/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/17/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/17/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/17/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/17/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/17/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/17/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/17/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/17/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/17/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/17/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/17/tables/0/columns/0/label": "Text-format label", "/versions/17/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "d6c5e007e4944c557640fea05a1d4884e49e1d5d13711f08dcd653cb7aa1acf2", "canonical_center_text_hash": "ff3bae482400ee83dd0789eeae5dfc214589c3c9234e60cbeabc21fb1d6e204c"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/17/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v17 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/17/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "18": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "63062406215ef682db58a20cb932ef30b83a6dca24557b625cf199d429fc8140", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "27a85416bafed557006c705ab5d0c5dce3d3c1702812bb54d136f2ac4c41055a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=18", "label": "EXPLAIN"}, {"url": "/docs/18/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/18/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=18", "label": "work_mem"}], "release": {"ref": "PostgreSQL 18.6 source archive", "label": "18.6", "major": "18", "channel": "stable", "revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f", "source_url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 1474, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1474", "sha256": "34c86d6070224a0e981efef51f79101d6d505e5874f1684ace183034bab14bb4", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 269, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:269", "sha256": "f8a06a3f539077249b20664b2812433db6d7bd12b2c0ca633525db43d06f112a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "63062406215ef682db58a20cb932ef30b83a6dca24557b625cf199d429fc8140", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "52422b327a8049fbbb20d8b96008a0fc0a6fafa60f7eff3c695d5b2e83830120", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "27a85416bafed557006c705ab5d0c5dce3d3c1702812bb54d136f2ac4c41055a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/18/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "18", "build_id": 107, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "d2f749744b3ac5aa2eb0154f295e8163903cd20fcc130c74c6172cdf2ae3a9df", "fragment_sha256": "15fbdf84b8f499253ade4f4a5841de138619a9933b93cc241d431dbe922fa40c", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:08e987a66af27b98444a8057c256314eafa13611a3fb9e888214fc436824244b", "translated_from_revision": null}, "body_sha256": "f9a755e48ba6ab095f7a4d4879d97d67294b0532d6414f3e0bd78e00f611b67c", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "18", "text_hash": "03d703dc8343ffb80861926977139ec53b456cf9eed023e89c4f54ef1dd89bd0", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/18/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "18", "build_id": 107, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "d2f749744b3ac5aa2eb0154f295e8163903cd20fcc130c74c6172cdf2ae3a9df", "fragment_sha256": "15fbdf84b8f499253ade4f4a5841de138619a9933b93cc241d431dbe922fa40c", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:08e987a66af27b98444a8057c256314eafa13611a3fb9e888214fc436824244b", "translated_from_revision": null}, "body_sha256": "f9a755e48ba6ab095f7a4d4879d97d67294b0532d6414f3e0bd78e00f611b67c", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/18/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/18/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "18", "link_map": {"/zh/docs/18/sql-explain.html": "/docs/18/sql-explain.html", "/zh/docs/18/using-explain.html": "/docs/18/using-explain.html"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/18/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/18/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "e1afbd2babe2426433a0a384c37347bf22dc91684aee1254469fe6d97da91b52", "content_hash": "03d703dc8343ffb80861926977139ec53b456cf9eed023e89c4f54ef1dd89bd0", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/18/facts/0/label": "Core node tag", "/versions/18/facts/1/label": "Structured EXPLAIN Node Type", "/versions/18/facts/2/label": "Inputs", "/versions/18/facts/2/value": "A CTE plan and shared tuplestore", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "CTE result tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/tables/0/title": "EXPLAIN labels in this source build", "/versions/18/related/1/label": "Using EXPLAIN", "/versions/18/related/2/label": "Parallel plans", "/versions/18/sections/0/title": "EXPLAIN names and attributes", "/versions/18/sections/1/title": "Memory and temporary storage", "/versions/18/sections/2/title": "Parallel execution and instrumentation", "/versions/18/sections/3/title": "Executor implementation notes", "/versions/18/sections/4/title": "EXPLAIN identity in core source", "/versions/18/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/18/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/18/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/18/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/18/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/18/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/18/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/18/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/18/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/18/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/18/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/18/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/18/tables/0/columns/0/label": "Text-format label", "/versions/18/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "bac545fc08b3767952273b06e698dfa9acf7a2e8c5776945a6b104e56d235b6d", "canonical_center_text_hash": "03d703dc8343ffb80861926977139ec53b456cf9eed023e89c4f54ef1dd89bd0"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/18/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/18/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "center_zh_rendered": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/docs/18/sql-explain.html\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/docs/18/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "19": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "8f2c49a856d16aab38cdb9bc9b3031bc943e2e7ef7d142efa7077e266f5f1650", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, {"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "cda3af245b88d079a32616b4cc5316913d349ba3acaab5fc1fd8aec479cc51ee", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}], "mechanism": "tuplestore", "description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=19", "label": "EXPLAIN"}, {"url": "/docs/19/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/19/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=19", "label": "work_mem"}], "release": {"ref": "PostgreSQL 19rc1 source archive", "label": "19rc1", "major": "19", "channel": "preview", "revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701", "source_url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "line": 1486, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1486", "sha256": "8b115b1c194a4b54ae630209a741e293b1df49a9052f10b2de9ca092a48998e3", "archive_sha256": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, {"url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "line": 269, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:269", "sha256": "5e39b2037bed672da55104229ecc32da5abde44c26bcad01479edcfa044d09ed", "archive_sha256": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, {"url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "8f2c49a856d16aab38cdb9bc9b3031bc943e2e7ef7d142efa7077e266f5f1650", "archive_sha256": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, {"url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "8d7bcf0e3b0d990a7bf35af47099d6d77207594b3136ff17104ed80bfaa47022", "archive_sha256": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, {"url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "path": "src/backend/utils/sort/tuplestore.c", "label": "src/backend/utils/sort/tuplestore.c", "sha256": "cda3af245b88d079a32616b4cc5316913d349ba3acaab5fc1fd8aec479cc51ee", "archive_sha256": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/19/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "19", "build_id": 109, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "9bbb1ef5924e4788a3dc2642828383c67ab8651fb6b0e45924c454f095b0ff47", "fragment_sha256": "1ceb32499da15c4bcec0644765b693adbc1991296745e00460ce28d06d701ef3", "source_revision": "sha256:af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:65fda1f1b62a89992b84014c9157e61b67dbe8190e93945826efec668fad038c", "translated_from_revision": "sha256:af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "body_sha256": "6f8fa8a2d6697746cb68980a0ca077e8c1cee610cda74f32b954787ee6533647", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "19", "text_hash": "47a7e5c64d40f7a4efa45165d3ee3c75d55d05e8ca59b2a7aa0f64ea0abada8c", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/19/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "19", "build_id": 109, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "9bbb1ef5924e4788a3dc2642828383c67ab8651fb6b0e45924c454f095b0ff47", "fragment_sha256": "1ceb32499da15c4bcec0644765b693adbc1991296745e00460ce28d06d701ef3", "source_revision": "sha256:af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:65fda1f1b62a89992b84014c9157e61b67dbe8190e93945826efec668fad038c", "translated_from_revision": "sha256:af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "body_sha256": "6f8fa8a2d6697746cb68980a0ca077e8c1cee610cda74f32b954787ee6533647", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/19/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/19/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "19", "link_map": {"/zh/docs/19/sql-explain.html": "/docs/19/sql-explain.html", "/zh/docs/19/using-explain.html": "/docs/19/using-explain.html"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/19/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/19/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "df4fda7fee6a8317adc59f373518fc576c822b7776153e90e1491a3302e52b59", "content_hash": "47a7e5c64d40f7a4efa45165d3ee3c75d55d05e8ca59b2a7aa0f64ea0abada8c", "source_database": "center", "source_revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/19/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/19/facts/0/label": "Core node tag", "/versions/19/facts/1/label": "Structured EXPLAIN Node Type", "/versions/19/facts/2/label": "Inputs", "/versions/19/facts/2/value": "A CTE plan and shared tuplestore", "/versions/19/facts/3/label": "Output", "/versions/19/facts/3/value": "CTE result tuples", "/versions/19/facts/4/label": "Executor initializer", "/versions/19/facts/5/label": "Memory mechanism", "/versions/19/tables/0/title": "EXPLAIN labels in this source build", "/versions/19/related/1/label": "Using EXPLAIN", "/versions/19/related/2/label": "Parallel plans", "/versions/19/sections/0/title": "EXPLAIN names and attributes", "/versions/19/sections/1/title": "Memory and temporary storage", "/versions/19/sections/2/title": "Parallel execution and instrumentation", "/versions/19/sections/3/title": "Executor implementation notes", "/versions/19/sections/4/title": "EXPLAIN identity in core source", "/versions/19/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/19/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/19/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/19/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/19/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/19/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/19/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/19/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/19/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/19/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/19/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/19/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/19/tables/0/columns/0/label": "Text-format label", "/versions/19/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "db2140c1d870dc6f9a22d69e01294dec2b3dc907e52e1d2b7ffcd499b3317d18", "canonical_center_text_hash": "47a7e5c64d40f7a4efa45165d3ee3c75d55d05e8ca59b2a7aa0f64ea0abada8c"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/19/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/19/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "source_revalidation": {"kind": "static-same-version-source-and-manual-replay", "audit": "wiki-audit-20261023", "runtime_rerun": false, "compared_fields": "entity membership and source-derived facts; presentation markup normalized", "source_revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701", "previous_source_revision": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}}, "20": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "8f2c49a856d16aab38cdb9bc9b3031bc943e2e7ef7d142efa7077e266f5f1650", "archive_sha256": 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"https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "line": 1486, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1486", "sha256": "f82f238e2e6e249e10daf2e257728494ec10de1695fcf05feaadfd7f6bf78600", "archive_sha256": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, {"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "line": 269, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:269", "sha256": "5e39b2037bed672da55104229ecc32da5abde44c26bcad01479edcfa044d09ed", "archive_sha256": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, {"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": 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"\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "20", "text_hash": "4323e57ccde07e0815a9410f43dbfda4a6673c0b7743db69c612fe76945738e9", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/devel/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "20", "build_id": 111, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "436517563e51b6d851ef143e70d01f5f68fe0a01e00a0d507e7bd79d7570aa25", "fragment_sha256": "f2d2c226e0479b8d931accead1f2cf7c1b8646afa24d8025ea5d5bcab837f779", "source_revision": "sha256:49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:98c980963b401d40bd50df72b909e7523e3148b8fdb48edd897de2efb67e5235", "translated_from_revision": "sha256:49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, "body_sha256": "6b71b6bd1b8ff479785899a1c98f1fa25f312eff609e3953210016ee3da9160a", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/devel/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/devel/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "20", "link_map": {"/zh/docs/devel/sql-explain.html": "/docs/devel/sql-explain.html", "/zh/docs/devel/using-explain.html": "/docs/devel/using-explain.html"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/devel/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/devel/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "12f7d048ca17efb8f05003534c7e34bdffda6db07a3ced1efa57af1446490752", "content_hash": "4323e57ccde07e0815a9410f43dbfda4a6673c0b7743db69c612fe76945738e9", "source_database": "center", "source_revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/summary": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/category": "Scan", "/versions/20/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/20/facts/0/label": "Core node tag", "/versions/20/facts/1/label": "Structured EXPLAIN Node Type", "/versions/20/facts/2/label": "Inputs", "/versions/20/facts/2/value": "A CTE plan and shared tuplestore", "/versions/20/facts/3/label": "Output", "/versions/20/facts/3/value": "CTE result tuples", "/versions/20/facts/4/label": "Executor initializer", "/versions/20/facts/5/label": "Memory mechanism", "/versions/20/tables/0/title": "EXPLAIN labels in this source build", "/versions/20/related/1/label": "Using EXPLAIN", "/versions/20/related/2/label": "Parallel plans", "/versions/20/sections/0/title": "EXPLAIN names and attributes", "/versions/20/sections/1/title": "Memory and temporary storage", "/versions/20/sections/2/title": "Parallel execution and instrumentation", "/versions/20/sections/3/title": "Executor implementation notes", "/versions/20/sections/4/title": "EXPLAIN identity in core source", "/versions/20/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/20/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/20/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/20/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/20/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/20/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/20/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/20/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/20/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/20/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/20/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/20/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/20/tables/0/columns/0/label": "Text-format label", "/versions/20/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "14f5ec590b9f69bfc4ff34a654aff9b45c9d7eee68d3d61b3b7c4c5a88a1ead0", "canonical_center_text_hash": "4323e57ccde07e0815a9410f43dbfda4a6673c0b7743db69c612fe76945738e9"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/devel/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/devel/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "source_revalidation": {"kind": "static-same-version-source-and-manual-replay", "audit": "wiki-audit-20261023", "runtime_rerun": false, "compared_fields": "entity membership and source-derived facts; presentation markup normalized", "source_revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac", "previous_source_revision": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41"}}}}, "snapshot": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeCtescan.c", "label": "src/backend/executor/nodeCtescan.c", "sha256": "63062406215ef682db58a20cb932ef30b83a6dca24557b625cf199d429fc8140", "archive_sha256": 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The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=18", "label": "EXPLAIN"}, {"url": "/docs/18/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/18/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}, {"url": "/wiki/guc/work_mem/?v=18", "label": "work_mem"}], "release": {"ref": "PostgreSQL 18.6 source archive", "label": "18.6", "major": "18", "channel": "stable", "revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f", "source_url": 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"zh-Hans", "version": "18", "build_id": 107, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "d2f749744b3ac5aa2eb0154f295e8163903cd20fcc130c74c6172cdf2ae3a9df", "fragment_sha256": "15fbdf84b8f499253ade4f4a5841de138619a9933b93cc241d431dbe922fa40c", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:08e987a66af27b98444a8057c256314eafa13611a3fb9e888214fc436824244b", "translated_from_revision": null}, "body_sha256": "f9a755e48ba6ab095f7a4d4879d97d67294b0532d6414f3e0bd78e00f611b67c", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "node_tag": "T_CteScan", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "CteScan", "locale": "zh-Hans", "source": {"key": "cte-scan", "locale": "zh-Hans", "version": "18", "text_hash": "03d703dc8343ffb80861926977139ec53b456cf9eed023e89c4f54ef1dd89bd0", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_CteScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "CTE Scan"}, {"label": "\u8f93\u5165", "value": "CTE \u6267\u884c\u8ba1\u5212\u53ca\u5171\u4eab\u7684 tuplestore"}, {"label": "\u8f93\u51fa", "value": "CTE \u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitCteScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "tuplestore"}], "tables": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "zh_from": {"kind": "same-version-chinese-manual-with-authored-translation-of-reviewed-guidance", "manual": {"url": "/zh/docs/18/using-explain.html", "anchor": "", "locale": "zh-Hans", "version": "18", "build_id": 107, "page_key": "using-explain.html", "extraction": "concept-introduction", "source_hash": "d2f749744b3ac5aa2eb0154f295e8163903cd20fcc130c74c6172cdf2ae3a9df", "fragment_sha256": "15fbdf84b8f499253ade4f4a5841de138619a9933b93cc241d431dbe922fa40c", "source_revision": "unknown:rendered-translation-baseline", "translation_revision": "git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:08e987a66af27b98444a8057c256314eafa13611a3fb9e888214fc436824244b", "translated_from_revision": null}, "body_sha256": "f9a755e48ba6ab095f7a4d4879d97d67294b0532d6414f3e0bd78e00f611b67c", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span class=\"productname\">PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em class=\"firstterm\">\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em class=\"firstterm\">\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a class=\"link\" href=\"/zh/docs/18/sql-explain.html\"><code class=\"command\">EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code class=\"command\">VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code class=\"command\">ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code class=\"command\">EXPLAIN</code> \u9ed8\u8ba4\u7684<span class=\"quote\">\u201c<span class=\"quote\">text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code class=\"command\">EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/18/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "summary": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "version": "18", "link_map": {"/zh/docs/18/sql-explain.html": "/docs/18/sql-explain.html", "/zh/docs/18/using-explain.html": "/docs/18/using-explain.html"}, "body_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/18/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/18/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "body_sha256": "e1afbd2babe2426433a0a384c37347bf22dc91684aee1254469fe6d97da91b52", "content_hash": "03d703dc8343ffb80861926977139ec53b456cf9eed023e89c4f54ef1dd89bd0", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "CTE Scan", "identity": "CTE Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "strategies": [], "description": ["\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002"], "sections_zh": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aCTE Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u6b64\u8282\u70b9\u4f7f\u7528 work_mem \u521b\u5efa tuplestore\u3002tuplestore \u53ef\u4ee5\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u79fb\u5230\u4e34\u65f6\u6587\u4ef6\uff0c\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 work_mem \u9650\u5236\u4e86\u8282\u70b9\u7684\u5168\u90e8\u5185\u5b58\u5206\u914d\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["\u5982\u679c\u5c1a\u672a\u5230\u8fbe tuplestore \u672b\u5c3e\uff0c\u6216\u6b63\u5728\u53cd\u5411\u626b\u63cf\uff0c\u5219\u5c1d\u8bd5\u4ece tuplestore \u83b7\u53d6\u5143\u7ec4\u3002", "\u5728\u5143\u7ec4\u5b58\u50a8\u672b\u5c3e\u53cd\u8f6c\u626b\u63cf\u65b9\u5411\u65f6\uff0c\u7b2c\u4e00\u6b21 gettupleslot \u4f1a\u53d6\u5f97\u6700\u540e\u6dfb\u52a0\u7684\u5143\u7ec4\uff1b\u4f46\u82e5\u53ef\u80fd\uff0c\u6211\u4eec\u5e0c\u671b\u8fd4\u56de\u5b83\u4e4b\u524d\u7684\u90a3\u4e2a\uff0c\u56e0\u6b64\u989d\u5916\u8bfb\u53d6\u4e00\u6b21\u3002", "\u82e5\u80fd\u4ece\u5143\u7ec4\u5b58\u50a8\u518d\u53d6\u5f97\u4e00\u4e2a\u5143\u7ec4\uff0c\u5219\u8fd4\u56de\u5b83\u3002", "\u6ce8\u610f\uff1a\u8c03\u7528 tuplestore_gettupleslot \u65f6\u5fc5\u987b\u4f7f\u7528 copy=true\uff0c\u56e0\u4e3a\u5176\u4ed6\u8282\u70b9\u5171\u4eab\u8be5\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u53ef\u80fd\u5728\u4e0b\u6b21\u8c03\u7528\u4e4b\u524d\u5199\u5165\u5b83\u3002", "\u6ce8\u610f\uff1aeof_cte \u72b6\u6001\u53d8\u91cf\u7528\u4e8e\u907f\u514d\u7ee7\u7eed\u8c03\u7528 CTE \u8ba1\u5212\u3002\u9057\u61be\u7684\u662f\u5b83\u4e0d\u53ef\u7701\u7565\uff0c\u56e0\u4e3a\u67d0\u4e9b\u8ba1\u5212\u8282\u70b9\u5df2\u7ecf\u8fd4\u56de NULL \u540e\u82e5\u518d\u6b21\u88ab\u8c03\u7528\uff0c\u5e76\u4e0d\u80fd\u7a33\u5065\u5904\u7406\u3002"]}, {"code": "case T_CteScan:\n\t\t\tpname = sname = \"CTE Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Reads the shared tuplestore of a common-table-expression plan, asking that plan for more rows when needed.", "/versions/18/facts/0/label": "Core node tag", "/versions/18/facts/1/label": "Structured EXPLAIN Node Type", "/versions/18/facts/2/label": "Inputs", "/versions/18/facts/2/value": "A CTE plan and shared tuplestore", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "CTE result tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/tables/0/title": "EXPLAIN labels in this source build", "/versions/18/related/1/label": "Using EXPLAIN", "/versions/18/related/2/label": "Parallel plans", "/versions/18/sections/0/title": "EXPLAIN names and attributes", "/versions/18/sections/1/title": "Memory and temporary storage", "/versions/18/sections/2/title": "Parallel execution and instrumentation", "/versions/18/sections/3/title": "Executor implementation notes", "/versions/18/sections/4/title": "EXPLAIN identity in core source", "/versions/18/memory/description": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/18/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/18/sections/0/paragraphs/1": "Text names recorded by this source: CTE Scan.", "/versions/18/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/18/sections/1/paragraphs/0": "This node creates a tuplestore with work_mem. The tuplestore can move stored tuples to temporary files; this does not make work_mem a cap on every allocation made by the node.", "/versions/18/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/18/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/18/sections/3/paragraphs/0": "If we are not at the end of the tuplestore, or are going backwards, try to fetch a tuple from tuplestore.", "/versions/18/sections/3/paragraphs/1": "When reversing direction at tuplestore EOF, the first gettupleslot call will fetch the last-added tuple; but we want to return the one before that, if possible. So do an extra fetch.", "/versions/18/sections/3/paragraphs/2": "If we can fetch another tuple from the tuplestore, return it.", "/versions/18/sections/3/paragraphs/3": "Note: we have to use copy=true in the tuplestore_gettupleslot call, because we are sharing the tuplestore with other nodes that might write into the tuplestore before we get called again.", "/versions/18/sections/3/paragraphs/4": "Note: the eof_cte state variable exists to short-circuit further calls of the CTE plan. It's not optional, unfortunately, because some plan node types are not robust about being called again when they've already returned NULL.", "/versions/18/tables/0/columns/0/label": "Text-format label", "/versions/18/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "bac545fc08b3767952273b06e698dfa9acf7a2e8c5776945a6b104e56d235b6d", "canonical_center_text_hash": "03d703dc8343ffb80861926977139ec53b456cf9eed023e89c4f54ef1dd89bd0"}, "evidence_kind": "source and documentation", "explain_names": ["CTE Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002", "comparison_data": {"node_tag": "T_CteScan", "strategies": [], "text_names": ["CTE Scan"], "initializer": "ExecInitCteScan", "partial_modes": [], "memory_mechanism": "tuplestore", "parallel_callbacks": []}, "comparison_hash": "b99869b4fa614eb4c00675da9cf14c4d017018c55dbc2f0ea18d335cccb0a3aa", "manual_language": "zh", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeCtescan.c"}, "parallel_callbacks": [], "description_zh_html": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/zh/docs/18/sql-explain.html\" rel=\"nofollow\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/zh/docs/18/using-explain.html\" rel=\"nofollow\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>", "center_zh_rendered": "<p>\u8bfb\u53d6\u516c\u5171\u8868\u8868\u8fbe\u5f0f\u8ba1\u5212\u7684\u5171\u4eab\u5143\u7ec4\u5b58\u50a8\uff0c\u5e76\u5728\u9700\u8981\u65f6\u8bf7\u6c42\u8be5\u8ba1\u5212\u751f\u6210\u66f4\u591a\u884c\u3002</p><p>\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1a<code>T_CteScan</code>\uff1bEXPLAIN \u540d\u79f0\uff1a<code>CTE Scan</code>\u3002</p><p>\u672c\u7248\u672c\u6e90\u7801\u4e2d\u7684\u5e76\u884c\u6267\u884c\u6216\u89c2\u6d4b\u56de\u8c03\uff1a\u8be5\u8282\u70b9\u5b9e\u73b0\u4e2d\u672a\u63d0\u53d6\u5230\u6b64\u7c7b\u56de\u8c03\u3002\u56de\u8c03\u7684\u5b58\u5728\u4e0d\u8868\u793a\u8be5\u8282\u70b9\u5fc5\u7136\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\uff1b\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u4e2d\u6267\u884c\u4e5f\u4e0d\u7b49\u4e8e\u5177\u6709\u5e76\u884c\u611f\u77e5\u80fd\u529b\u3002</p><p>\u8be5\u8282\u70b9\u4f7f\u7528\u53d7 <code>work_mem</code> \u5f71\u54cd\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5fc5\u8981\u65f6\u53ef\u5c06\u5b58\u50a8\u7684\u5143\u7ec4\u5199\u5165\u4e34\u65f6\u6587\u4ef6\u3002\u8fd9\u5e76\u4e0d\u8868\u793a <code>work_mem</code> \u9650\u5236\u4e86\u8be5\u8282\u70b9\u7684\u6240\u6709\u5185\u5b58\u5206\u914d\u3002</p><h3>\u540c\u7248\u672c\u4e2d\u6587\u624b\u518c\u8282\u9009</h3><p>\n<span>PostgreSQL</span> \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a<em>\u67e5\u8be2\u8ba1\u5212</em>\u3002\u9009\u62e9\u4e0e\u67e5\u8be2\u7ed3\u6784\u548c\u6570\u636e\u7279\u6027\u76f8\u5339\u914d\u7684\u6b63\u786e\u8ba1\u5212\uff0c\u5bf9\u83b7\u5f97\u826f\u597d\u7684\u6027\u80fd\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u6b64\u7cfb\u7edf\u5185\u7f6e\u4e86\u4e00\u4e2a\u590d\u6742\u7684<em>\u89c4\u5212\u5668</em>\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 <a href=\"/docs/18/sql-explain.html\"><code>EXPLAIN</code></a> \u547d\u4ee4\u67e5\u770b\u89c4\u5212\u5668\u4e3a\u4efb\u610f\u67e5\u8be2\u751f\u6210\u7684\u67e5\u8be2\u8ba1\u5212\u3002\u8bfb\u61c2\u8ba1\u5212\u662f\u4e00\u95e8\u9700\u8981\u7ecf\u9a8c\u79ef\u7d2f\u7684\u6280\u80fd\uff0c\u672c\u8282\u5c06\u5c1d\u8bd5\u4ecb\u7ecd\u5176\u4e2d\u7684\u57fa\u7840\u77e5\u8bc6\u3002\n   </p><p>\n    \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 <code>VACUUM ANALYZE</code> \u7684\u56de\u5f52\u6d4b\u8bd5\u6570\u636e\u5e93\uff0c\u4f7f\u7528\u7684\u662f v18 \u5f00\u53d1\u7248\u672c\u6e90\u7801\u3002\u5982\u679c\u81ea\u884c\u5c1d\u8bd5\u8fd9\u4e9b\u793a\u4f8b\uff0c\u901a\u5e38\u5e94\u5f53\u80fd\u5f97\u5230\u76f8\u8fd1\u7684\u7ed3\u679c\uff0c\u4f46\u4f30\u8ba1\u4ee3\u4ef7\u548c\u884c\u8ba1\u6570\u53ef\u80fd\u7565\u6709\u5dee\u5f02\uff0c\u56e0\u4e3a <code>ANALYZE</code> \u751f\u6210\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u81ea\u968f\u673a\u91c7\u6837\u800c\u975e\u7cbe\u786e\u8ba1\u6570\uff0c\u800c\u4e14\u4ee3\u4ef7\u672c\u8eab\u5728\u67d0\u79cd\u7a0b\u5ea6\u4e0a\u4e5f\u4f9d\u8d56\u4e8e\u5e73\u53f0\u3002\n   </p><p>\n    \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 <code>EXPLAIN</code> \u9ed8\u8ba4\u7684<span>\u201c<span>text</span>\u201d</span>\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 <code>EXPLAIN</code> \u7684\u8f93\u51fa\u4ea4\u7ed9\u7a0b\u5e8f\u505a\u8fdb\u4e00\u6b65\u5206\u6790\uff0c\u5219\u5e94\u6539\u7528\u673a\u5668\u53ef\u8bfb\u7684\u8f93\u51fa\u683c\u5f0f\uff08XML\u3001JSON \u6216 YAML\uff09\u3002\n   </p><p><a href=\"/docs/18/using-explain.html\">\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587</a>\u3002</p><p>\u672c\u9875\u5f00\u5934\u7684\u4e2d\u6587\u8bf4\u660e\u4e3a PG.CENTER \u5bf9\u7f16\u8f91\u8bf4\u660e\u7684\u7ffb\u8bd1\uff1b\u624b\u518c\u8282\u9009\u4fdd\u7559\u5bf9\u5e94\u7248\u672c\u4e2d\u6587\u6587\u6863\u539f\u6587\u3002\u6e90\u7801\u4fe1\u606f\u53ca\u624b\u518c\u793a\u4f8b\u4e0d\u4ee3\u8868\u91cd\u65b0\u8fdb\u884c\u8fc7\u8fd0\u884c\u6d4b\u8bd5\u3002</p>"}, "comparison": {"left": "17", "right": "18", "status": "unchanged", "diff": ""}}