\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
PostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
PostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "762b4f7f94839f50941acf54af184b063613b1d824f3ef13d21ba0e3a675ef05", "content_hash": "0bf2d8e5f74f40b796a919d681244d9922fa409825b63f592a97ef5e73a98ed3", "source_database": "center", "source_revision": "94a4b2528372458e5662c18d406629266667c437198160a18cdfd2c4a4d6eee9"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/10/facts/3/label": "Output", "/versions/10/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/10/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/10/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/10/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/10/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "4c380f1cb00f31c46cf18a7700d80bbc8dee05326b908384de956e96987b2b00", "canonical_center_text_hash": "0bf2d8e5f74f40b796a919d681244d9922fa409825b63f592a97ef5e73a98ed3"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
PostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "11": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "4fa1950f44986d3e7be4a776dc77d0e488d19aa0cd7e77b98837a2536d9bfd8b", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1102, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1102", "sha256": "9df8400c1a4377179572ceb916d6020fca4e2760f74bf416d77ed97476523bbd", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, {"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "line": 272, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:272", "sha256": "95ef4d4a5df4c29f14af9763fae2c530449bdacdf3853d9ff297adf1fed6153b", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, {"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "4fa1950f44986d3e7be4a776dc77d0e488d19aa0cd7e77b98837a2536d9bfd8b", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, {"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "5e0511194183800e8d6eb293fd4b40639c7d3118e2d199c8e7865ba4fa4cf67f", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}], "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": "95523e41fc9155397a33098082492dc3e116cebdbf6974846cd0e4cab15b8d08", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "11", "text_hash": "af2a9dc97f02e754ee1c36630d611791a57e6b996cdff85474f463b1b3e1c7a6", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "95523e41fc9155397a33098082492dc3e116cebdbf6974846cd0e4cab15b8d08", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "2247e746618ffaba954b8ddefe831cdcfab606ada6dd3a6a3d78d188f484ddd8", "content_hash": "af2a9dc97f02e754ee1c36630d611791a57e6b996cdff85474f463b1b3e1c7a6", "source_database": "center", "source_revision": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/11/facts/3/label": "Output", "/versions/11/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/11/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/11/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/11/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/11/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "4cedc0d7b35f540f461ba2036e5b21db9f15b3560a6b01c648825d73a1a7fad6", "canonical_center_text_hash": "af2a9dc97f02e754ee1c36630d611791a57e6b996cdff85474f463b1b3e1c7a6"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "12": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "9fae86882498c6e89012357ac25d95788b6c2070b8a309fd3548800c23176c6f", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1173, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1173", "sha256": "d02ea84fdaa201de5d9360645a9f24bfbd2c31f7d45a639e09560ac0e6b6471d", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "line": 272, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:272", "sha256": "311b17379fe54e3f342fe5ad41c43afbdfa1b844978db2bb2eb22b82520d3256", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "9fae86882498c6e89012357ac25d95788b6c2070b8a309fd3548800c23176c6f", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "b0c4a0aeb48660ce06e5e700d5529ca9066fd16682bd15783d6e71b5420b07b0", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}], "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": "83d369250ac5b79ca362424d2a21845d1ec957b75db274be3fc2488c484401f9", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "12", "text_hash": "74c04d3cac85f1444938524866deaa3da80cfd7d89615b43b93e15c2e3bc59eb", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "83d369250ac5b79ca362424d2a21845d1ec957b75db274be3fc2488c484401f9", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "46a1a8cf68545be11d68f42c76566db02e651ee164a22677509e4bf6784d276a", "content_hash": "74c04d3cac85f1444938524866deaa3da80cfd7d89615b43b93e15c2e3bc59eb", "source_database": "center", "source_revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/12/facts/3/label": "Output", "/versions/12/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/12/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/12/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/12/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/12/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "971af69794889d249d9c8c3bb460c4067f019fa73c0c2182a0a8b4a61e99fffd", "canonical_center_text_hash": "74c04d3cac85f1444938524866deaa3da80cfd7d89615b43b93e15c2e3bc59eb"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "13": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "1fda168d74d731055bb24867a1c221b0a60a69aeeac6f15c606cc54261b01dd4", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1231, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1231", "sha256": "541713e0e7f1c9cc352c2b6028964d440c19d2678a4463000094c24a88c1e730", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "line": 272, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:272", "sha256": "d085ee99acfa00587e6ade3a1d9f8108a0566beedbbee3f54a50c9fc0cc2e875", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "1fda168d74d731055bb24867a1c221b0a60a69aeeac6f15c606cc54261b01dd4", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "dcb296833777b02008c4b6bae8e8f7c6423b7ffba21f36702597c9d596d039ab", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}], "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": "c06043fea1fd20d619767bafb212dde763e6ffde6e59051bd6e0dcc91d25a4d3", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "13", "text_hash": "ad31e35af6c9c4edc662a3941b3a92735cf702af496d5261d3763296508b0cb7", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "c06043fea1fd20d619767bafb212dde763e6ffde6e59051bd6e0dcc91d25a4d3", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "087df2d5403a5dfaa9ed8cda7e4652c60f34fe3870b6b266fa116fd7800f6652", "content_hash": "ad31e35af6c9c4edc662a3941b3a92735cf702af496d5261d3763296508b0cb7", "source_database": "center", "source_revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/13/facts/3/label": "Output", "/versions/13/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/13/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/13/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/13/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/13/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "7a68f0602c30e47526a02b306b9820c929e32f6b61be4cd7f1bade65a5cf69ae", "canonical_center_text_hash": "ad31e35af6c9c4edc662a3941b3a92735cf702af496d5261d3763296508b0cb7"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "14": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "0de75c1f6c5b363fb0bd152b3b341bbfadaeea0e4074167221dc6d8bbfc053c3", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1270, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1270", "sha256": "e091be4e2a083b8dea39ccd09beedede22c1716ef974da66c214a44f48be8c41", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "72da1c5ad457f1d92a39ab73531701794df858419e3b89d6e6cb7079634e68fa", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "0de75c1f6c5b363fb0bd152b3b341bbfadaeea0e4074167221dc6d8bbfc053c3", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "302f51a16b570dba7ec4e7bc045f7df5800d21630280354d1a24025f3baec75d", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}], "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": "584c9770b3b44ab7b275c6d4d652f664bde896f5f71eff99a0dd687a2ed55427", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "14", "text_hash": "13c7e76065f8bdff564e18ec5892dd78227bf58e79e06270d1f0e5d686f84c67", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "584c9770b3b44ab7b275c6d4d652f664bde896f5f71eff99a0dd687a2ed55427", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "10359ffe23feb343a680023a4f4f57844dfb80f7e78e08321b8b08d444498403", "content_hash": "13c7e76065f8bdff564e18ec5892dd78227bf58e79e06270d1f0e5d686f84c67", "source_database": "center", "source_revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/14/facts/3/label": "Output", "/versions/14/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/14/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/14/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/14/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/14/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "65d8282139f4252d001d9e1c28b1403e78c0fc4b2386b3418eb4869bf4043c9c", "canonical_center_text_hash": "13c7e76065f8bdff564e18ec5892dd78227bf58e79e06270d1f0e5d686f84c67"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "15": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "264a3b9156dedf3f6aad05c08a91a1d4fc0f35b9cecc7da2518e3a8366aada26", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1273, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1273", "sha256": "bb3b442d0f1b098aa8707335250102f027a596cd94117308bd16d1d36b258f5c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "19836c50a272741a4eac653541e655437c2e00710a541e5348d6a277d0669d7c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "264a3b9156dedf3f6aad05c08a91a1d4fc0f35b9cecc7da2518e3a8366aada26", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "fb4a4c8165495299131173680bc02a950d88e1ff610231fd97997bc0c9afc1d7", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}], "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": "364a90684afbe25a63c827f19205ec565a4f04106556a411793b7113ca053694", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "15", "text_hash": "0bd0d374759d011f6334fa842d1d411099af0e3a1f67c30771e35a0440a944a6", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "364a90684afbe25a63c827f19205ec565a4f04106556a411793b7113ca053694", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "0ea80502a2ab34e7e3129e97d562c1712b0aecf609a27d97f02290942dc7ddcd", "content_hash": "0bd0d374759d011f6334fa842d1d411099af0e3a1f67c30771e35a0440a944a6", "source_database": "center", "source_revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/15/facts/3/label": "Output", "/versions/15/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/15/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/15/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/15/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/15/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "86b65d66a49bd27fa3978b90816182e97c0d984ac6b293cd184adf68d075427d", "canonical_center_text_hash": "0bd0d374759d011f6334fa842d1d411099af0e3a1f67c30771e35a0440a944a6"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "16": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "689cacb95aee091eee43e5c464762c08c9ae55c2524e2a37021e913d7aa27720", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1306, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1306", "sha256": "8e017f0116dbea471339b40c37a667cc9f95039e7e0329c783e5e8ce194de7e1", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "e48c08e555f8cb4e4bb43df516c4b8906ce9bc374b2a745d98a1fc8c22cc5099", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "689cacb95aee091eee43e5c464762c08c9ae55c2524e2a37021e913d7aa27720", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "97db47353db76326b874589a5ad0a04501cc74cd72e237e7bd956e7472c41f1f", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}], "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": "a856b5ba0945a6a55778ca6762030bb24ca8ed30bc94e13abacb2378ee218ba6", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "16", "text_hash": "025eebd6a3949831edb902da9360c4ba71c24cabbf7133e22b06791b059e1936", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "a856b5ba0945a6a55778ca6762030bb24ca8ed30bc94e13abacb2378ee218ba6", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "925a21b72fdd47b6c0df0662aaa213a23770bb5ccea090f3627d17459002fb2e", "content_hash": "025eebd6a3949831edb902da9360c4ba71c24cabbf7133e22b06791b059e1936", "source_database": "center", "source_revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/16/facts/3/label": "Output", "/versions/16/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/16/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/16/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/16/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/16/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "9ac0c7d4425c5730db39e5d513ea3e036dce9cf4d4fa9862431ef6ba9639b5bd", "canonical_center_text_hash": "025eebd6a3949831edb902da9360c4ba71c24cabbf7133e22b06791b059e1936"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "17": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "bf5b6c9b5f7880ae325cac7d7fb2788f9320a2c2d3c4bea5d311554bb1747787", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1495, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1495", "sha256": "741251b1a3b6d269a52a673d42eb63b02e13a5872db7b359b137086ab21b63c8", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "a77576e158b94cb01fa8c5174ba133004eabdd727660323f8afc66c8d2e757b8", "archive_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "bf5b6c9b5f7880ae325cac7d7fb2788f9320a2c2d3c4bea5d311554bb1747787", "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"}], "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": "a938bfeb9b8e4ca9a7ca1d5d6dcc910685fa4c44bbb2059ca44233714e2d8618", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "17", "text_hash": "d6bb5d278fea910c998ab55d73628ef6d0ceae2d6a5e9657e244b9be6956cba2", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "a938bfeb9b8e4ca9a7ca1d5d6dcc910685fa4c44bbb2059ca44233714e2d8618", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "ef4e7799e76166ba5791afaa65f712d5b3e53539eb54923737b1c8285ce30dc8", "content_hash": "d6bb5d278fea910c998ab55d73628ef6d0ceae2d6a5e9657e244b9be6956cba2", "source_database": "center", "source_revision": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/17/facts/3/label": "Output", "/versions/17/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/17/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/17/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/17/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/17/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "306be3337e32d7399bd405e5cf91bc26115a34448a0a732da2f1e6f4daf19699", "canonical_center_text_hash": "d6bb5d278fea910c998ab55d73628ef6d0ceae2d6a5e9657e244b9be6956cba2"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "18": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "912d71e785d7f013d5889e3389deff289a01e35fa2c3aafa2345939fbb988834", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1480, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1480", "sha256": "34c86d6070224a0e981efef51f79101d6d505e5874f1684ace183034bab14bb4", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "f8a06a3f539077249b20664b2812433db6d7bd12b2c0ca633525db43d06f112a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "912d71e785d7f013d5889e3389deff289a01e35fa2c3aafa2345939fbb988834", "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"}], "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": "85d3445b2b87e7503368121132734f9960340ddbdf1f2803f9046c8b3de0af03", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "18", "text_hash": "05fef3feac907f3c7a03ec4c74dffc3d82c86e5cb083e0ab11cf8020f5d02621", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "85d3445b2b87e7503368121132734f9960340ddbdf1f2803f9046c8b3de0af03", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "5a8318e205fae3ed11ab9eace477d6992badbea1f660a9f04336a9982d49bbac", "content_hash": "05fef3feac907f3c7a03ec4c74dffc3d82c86e5cb083e0ab11cf8020f5d02621", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/18/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/18/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/18/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/18/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "fa34878823171ab8fbd554b0dd00c1cdb65f2b4cbe63602fc47b2d653ae690df", "canonical_center_text_hash": "05fef3feac907f3c7a03ec4c74dffc3d82c86e5cb083e0ab11cf8020f5d02621"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "center_zh_rendered": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "19": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "325ec9e512f41d7af663a4ffa78aca2618248a066e3c6068c2aff58f71882bda", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1492, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1492", "sha256": "8b115b1c194a4b54ae630209a741e293b1df49a9052f10b2de9ca092a48998e3", "archive_sha256": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, {"url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "5e39b2037bed672da55104229ecc32da5abde44c26bcad01479edcfa044d09ed", "archive_sha256": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, {"url": "https://ftp.postgresql.org/pub/source/v19rc1/postgresql-19rc1.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "325ec9e512f41d7af663a4ffa78aca2618248a066e3c6068c2aff58f71882bda", "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"}], "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": "cbfe33de487be2d425fdc61d03d48a056cdaab6ca36a9c857fa62189d93ccbde", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "19", "text_hash": "c7279201f719a1358dc7a6648ed1ed0004a92fed10d9ca22577d723e9b8fa282", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "cbfe33de487be2d425fdc61d03d48a056cdaab6ca36a9c857fa62189d93ccbde", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "fd72e6e93288cc12bf0431d960aa627325c6541bd3d6e6740c23f57e79eb1111", "content_hash": "c7279201f719a1358dc7a6648ed1ed0004a92fed10d9ca22577d723e9b8fa282", "source_database": "center", "source_revision": "af105fc8e960fc836a09fc2cd7f582b49fd17675d9d36631abe3a565bfd7d701"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/19/facts/3/label": "Output", "/versions/19/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/19/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/19/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/19/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/19/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "407997fe4f126ba468d315bb4d010d010cb85781a3c7138c809f3510bd27c11a", "canonical_center_text_hash": "c7279201f719a1358dc7a6648ed1ed0004a92fed10d9ca22577d723e9b8fa282"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "325ec9e512f41d7af663a4ffa78aca2618248a066e3c6068c2aff58f71882bda", "archive_sha256": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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=20", "label": "EXPLAIN"}, {"url": "/docs/devel/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/devel/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 20devel source archive", "label": "20devel", "major": "20", "channel": "devel", "revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac", "source_url": "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": 1492, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1492", "sha256": "f82f238e2e6e249e10daf2e257728494ec10de1695fcf05feaadfd7f6bf78600", "archive_sha256": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, {"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "5e39b2037bed672da55104229ecc32da5abde44c26bcad01479edcfa044d09ed", "archive_sha256": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, {"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "325ec9e512f41d7af663a4ffa78aca2618248a066e3c6068c2aff58f71882bda", "archive_sha256": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, {"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "aa3c27b465209c0ecd1f5e0186d39110a75ed7aafb9a196d483fccb5fc641c6b", "archive_sha256": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}], "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": "27181caace4626009154c8a3e14f05af26044bcb752efffbee7e99efcf38b57a", "runtime_rerun": false, "authored_translation": "authored-translation-of-reviewed-guidance", "source_facts_revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, "facts_zh": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "20", "text_hash": "9039a8d8c0663e25d25ef3d4c772693c94988fae7c9baf1a2c014e9bf45e30ea", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "27181caace4626009154c8a3e14f05af26044bcb752efffbee7e99efcf38b57a", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "92246fc86d8fc946d6e8b8017904621bf59c51e9792820b39ea9c685716c0eb9", "content_hash": "9039a8d8c0663e25d25ef3d4c772693c94988fae7c9baf1a2c014e9bf45e30ea", "source_database": "center", "source_revision": "49c73aa4c9cacef8ca979276a28ac416c08e9e54c9baee4ae5fd116a35fa13ac"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/category": "Scan", "/versions/20/description/0": "Reads the current working table of a recursive union.", "/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": "The recursive query working table", "/versions/20/facts/3/label": "Output", "/versions/20/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/20/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/20/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/20/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/20/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "bf229b0a2093c338034a354f0c860c62e49c24a0f5b7e229b30e930531c5e4eb", "canonical_center_text_hash": "9039a8d8c0663e25d25ef3d4c772693c94988fae7c9baf1a2c014e9bf45e30ea"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "912d71e785d7f013d5889e3389deff289a01e35fa2c3aafa2345939fbb988834", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "mechanism": "unclassified", "description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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"}], "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": 1480, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1480", "sha256": "34c86d6070224a0e981efef51f79101d6d505e5874f1684ace183034bab14bb4", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 279, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:279", "sha256": "f8a06a3f539077249b20664b2812433db6d7bd12b2c0ca633525db43d06f112a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeWorktablescan.c", "label": "src/backend/executor/nodeWorktablescan.c", "sha256": "912d71e785d7f013d5889e3389deff289a01e35fa2c3aafa2345939fbb988834", "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"}], "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": "85d3445b2b87e7503368121132734f9960340ddbdf1f2803f9046c8b3de0af03", "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_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "node_tag": "T_WorkTableScan", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "center_zh": {"title": "WorkTableScan", "locale": "zh-Hans", "source": {"key": "worktable-scan", "locale": "zh-Hans", "version": "18", "text_hash": "05fef3feac907f3c7a03ec4c74dffc3d82c86e5cb083e0ab11cf8020f5d02621", "collection": "plan", "dataset_hash": "7c31b524dfe136022d39a6ae8dcfac6b3bbd5f8fdaf422536599981252aff0c9", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "payload": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_WorkTableScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "WorkTable Scan"}, {"label": "\u8f93\u5165", "value": "\u9012\u5f52\u67e5\u8be2\u5de5\u4f5c\u8868"}, {"label": "\u8f93\u51fa", "value": "\u5de5\u4f5c\u8868\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitWorkTableScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "tables": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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": "85d3445b2b87e7503368121132734f9960340ddbdf1f2803f9046c8b3de0af03", "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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "summary": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "body_sha256": "5a8318e205fae3ed11ab9eace477d6992badbea1f660a9f04336a9982d49bbac", "content_hash": "05fef3feac907f3c7a03ec4c74dffc3d82c86e5cb083e0ab11cf8020f5d02621", "source_database": "center", "source_revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "tables_zh": [{"key": "explain-labels", "rows": [{"label": "WorkTable Scan", "identity": "WorkTable 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\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\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\uff1aWorkTable 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": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\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": ["\u6ce8\u610f\uff1a\u8fd9\u91cc\u6709\u610f\u4e0d\u652f\u6301\u53cd\u5411\u626b\u63cf\u3002\u867d\u7136\u589e\u52a0\u51e0\u884c\u4ee3\u7801\u5373\u53ef\u5b9e\u73b0\uff0c\u4f46\u8fd9\u4f1a\u8feb\u4f7f nodeRecursiveunion.c \u521b\u5efa\u542f\u7528\u53cd\u5411\u626b\u63cf\u7684\u5143\u7ec4\u5b58\u50a8\uff0c\u5e26\u6765\u6027\u80fd\u5f00\u9500\u3002\u5b9e\u9645\u4e0a\uff0c\u5de5\u4f5c\u8868\u8282\u70b9\u4e0d\u4f1a\u5728\u53ef\u6eda\u52a8\u6e38\u6807\u8ba1\u5212\u6811\u4e2d\u5904\u4e8e\u8db3\u591f\u9ad8\u7684\u4f4d\u7f6e\uff0c\u4e0d\u4f1a\u9047\u5230\u53cd\u5411\u626b\u63cf\u8981\u6c42\uff0c\u56e0\u6b64\u4e3a\u5176\u63d0\u4f9b\u652f\u6301\u4e0d\u503c\u5f97\u3002", "\u6ce8\u610f\uff1a\u8fd9\u91cc\u8fd8\u5047\u5b9a\u6b64\u8282\u70b9\u662f\u5de5\u4f5c\u8868\u7684\u552f\u4e00\u8bfb\u53d6\u8005\u3002\u56e0\u6b64\u65e0\u9700\u4e3a\u5143\u7ec4\u5b58\u50a8\u8bbe\u7f6e\u79c1\u6709\u8bfb\u53d6\u6307\u9488\uff0c\u4e5f\u4e0d\u5fc5\u8981\u6c42 tuplestore_gettupleslot \u590d\u5236\u5143\u7ec4\u3002", "\u4ece\u5143\u7ec4\u5b58\u50a8\u53d6\u5f97\u4e0b\u4e00\u4e2a\u5143\u7ec4\uff1b\u6ca1\u6709\u66f4\u591a\u5143\u7ec4\u65f6\u8fd4\u56de NULL\u3002", "WorkTableScanRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5de5\u4f5c\u8868\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7ec4\u3002\u8c03\u7528 ExecScan() \u5e76\u4f20\u5165\u76f8\u5e94\u7684\u8bbf\u95ee\u65b9\u6cd5\u51fd\u6570\u3002"]}, {"code": "case T_WorkTableScan:\n\t\t\tpname = sname = \"WorkTable 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 current working table of a recursive union.", "/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": "The recursive query working table", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Working-table 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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: WorkTable 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 extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/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": "Note: we intentionally do not support backward scan. Although it would take only a couple more lines here, it would force nodeRecursiveunion.c to create the tuplestore with backward scan enabled, which has a performance cost. In practice backward scan is never useful for a worktable plan node, since it cannot appear high enough in the plan tree of a scrollable cursor to be exposed to a backward-scan requirement. So it's not worth expending effort to support it.", "/versions/18/sections/3/paragraphs/1": "Note: we are also assuming that this node is the only reader of the worktable. Therefore, we don't need a private read pointer for the tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.", "/versions/18/sections/3/paragraphs/2": "Get the next tuple from tuplestore. Return NULL if no more tuples.", "/versions/18/sections/3/paragraphs/3": "WorkTableScanRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/18/sections/3/paragraphs/4": "Scans the worktable sequentially and returns the next qualifying tuple. We call the ExecScan() routine and pass it the appropriate access method functions.", "/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": "fa34878823171ab8fbd554b0dd00c1cdb65f2b4cbe63602fc47b2d653ae690df", "canonical_center_text_hash": "05fef3feac907f3c7a03ec4c74dffc3d82c86e5cb083e0ab11cf8020f5d02621"}, "evidence_kind": "source and documentation", "explain_names": ["WorkTable Scan"], "partial_modes": [], "description_zh": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002", "comparison_data": {"node_tag": "T_WorkTableScan", "strategies": [], "text_names": ["WorkTable Scan"], "initializer": "ExecInitWorkTableScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "71b471dbdc054af8e4fa93bbbd9076da1fe3facccf5d5a46389f2bab3721761d", "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/nodeWorktablescan.c"}, "parallel_callbacks": [], "description_zh_html": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
", "center_zh_rendered": "\u8bfb\u53d6\u9012\u5f52 UNION \u5f53\u524d\u7684\u5de5\u4f5c\u8868\u3002
\u6838\u5fc3\u8282\u70b9\u6807\u8bc6\uff1aT_WorkTableScan\uff1bEXPLAIN \u540d\u79f0\uff1aWorkTable Scan\u3002
\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
\nPostgreSQL \u4f1a\u4e3a\u6536\u5230\u7684\u6bcf\u4e2a\u67e5\u8be2\u5236\u5b9a\u4e00\u4e2a\u67e5\u8be2\u8ba1\u5212\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\u89c4\u5212\u5668\u6765\u5c3d\u91cf\u9009\u51fa\u597d\u7684\u8ba1\u5212\u3002\u53ef\u4ee5\u4f7f\u7528 EXPLAIN \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
\n \u672c\u8282\u4e2d\u7684\u793a\u4f8b\u53d6\u81ea\u6267\u884c\u8fc7 VACUUM ANALYZE \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 ANALYZE \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
\n \u8fd9\u4e9b\u793a\u4f8b\u4f7f\u7528 EXPLAIN \u9ed8\u8ba4\u7684\u201ctext\u201d\u8f93\u51fa\u683c\u5f0f\uff0c\u5b83\u7d27\u51d1\u4e14\u4fbf\u4e8e\u4eba\u5de5\u9605\u8bfb\u3002\u5982\u679c\u5e0c\u671b\u5c06 EXPLAIN \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
\u67e5\u770b\u5b8c\u6574\u4e2d\u6587\u624b\u518c\u4e0e\u4e0a\u4e0b\u6587\u3002
\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
"}, "comparison": {"left": "17", "right": "18", "status": "unchanged", "diff": ""}}