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\u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/10/description/0": "Scans the output of a subquery plan.", "/versions/10/facts/0/label": "Core node tag", "/versions/10/facts/1/label": "Structured EXPLAIN Node Type", "/versions/10/facts/2/label": "Inputs", "/versions/10/facts/2/value": "A subquery child plan", "/versions/10/facts/3/label": "Output", "/versions/10/facts/3/value": "Subquery result tuples", "/versions/10/facts/4/label": "Executor initializer", "/versions/10/facts/5/label": "Memory mechanism", "/versions/10/tables/0/title": "EXPLAIN labels in this source build", "/versions/10/related/1/label": "Using EXPLAIN", "/versions/10/related/2/label": "Parallel plans", "/versions/10/sections/0/title": "EXPLAIN names and attributes", "/versions/10/sections/1/title": "Memory and temporary storage", 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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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/10/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/10/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/10/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/10/sections/3/paragraphs/4": "Scans the subquery 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": "6aa2a5f7a5f9f2dd2cb88d208e66368a3b897e6a47f34a96bdab7f4a5fae1715"}, "evidence_kind": "source and documentation", "explain_names": ["Subquery Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_SubqueryScan", "strategies": [], "text_names": ["Subquery Scan"], "initializer": "ExecInitSubqueryScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "2c67fdef6b55d5dfeedc05274c332f8e523a7b8dd3ffef1c7cb79b9d6d33566f", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": 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"\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/11/description/0": "Scans the output of a subquery plan.", "/versions/11/facts/0/label": "Core node tag", "/versions/11/facts/1/label": "Structured EXPLAIN Node Type", "/versions/11/facts/2/label": "Inputs", "/versions/11/facts/2/value": "A subquery child plan", "/versions/11/facts/3/label": "Output", "/versions/11/facts/3/value": "Subquery result tuples", "/versions/11/facts/4/label": "Executor initializer", "/versions/11/facts/5/label": "Memory mechanism", "/versions/11/tables/0/title": "EXPLAIN labels in this source build", "/versions/11/related/1/label": "Using EXPLAIN", "/versions/11/related/2/label": "Parallel plans", "/versions/11/sections/0/title": "EXPLAIN names and attributes", "/versions/11/sections/1/title": "Memory and temporary storage", "/versions/11/sections/2/title": "Parallel execution and instrumentation", "/versions/11/sections/3/title": "Executor implementation notes", "/versions/11/sections/4/title": "EXPLAIN identity in core source", "/versions/11/memory/description": "This 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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/11/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/11/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/11/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/11/sections/3/paragraphs/4": "Scans the subquery 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": "7ac8d466049bfb7202a148940b228316a31e93e5482bd63d3be5e44a592caa94"}, "evidence_kind": "source and documentation", "explain_names": ["Subquery Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_SubqueryScan", "strategies": [], "text_names": ["Subquery Scan"], "initializer": "ExecInitSubqueryScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "2c67fdef6b55d5dfeedc05274c332f8e523a7b8dd3ffef1c7cb79b9d6d33566f", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeSubqueryscan.c"}, "parallel_callbacks": []}, "12": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SubqueryScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Subquery Scan"}, {"label": "\u8f93\u5165", "value": "\u5b50\u67e5\u8be2\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u5b50\u67e5\u8be2\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSubqueryScan"}, {"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/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "8dc515f106e256f74573d3aed45151285d42a25bd647383a5ee868f54cc10d76", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}], "mechanism": "unclassified", "description": "\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", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Subquery Scan", "identity": "Subquery 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": 1155, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1155", "sha256": "d02ea84fdaa201de5d9360645a9f24bfbd2c31f7d45a639e09560ac0e6b6471d", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "line": 242, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:242", "sha256": "311b17379fe54e3f342fe5ad41c43afbdfa1b844978db2bb2eb22b82520d3256", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "8dc515f106e256f74573d3aed45151285d42a25bd647383a5ee868f54cc10d76", "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"}], "node_tag": "T_SubqueryScan", "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\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/12/description/0": "Scans the output of a subquery plan.", "/versions/12/facts/0/label": "Core node tag", "/versions/12/facts/1/label": "Structured EXPLAIN Node Type", "/versions/12/facts/2/label": "Inputs", "/versions/12/facts/2/value": "A subquery child plan", "/versions/12/facts/3/label": "Output", "/versions/12/facts/3/value": "Subquery result tuples", "/versions/12/facts/4/label": "Executor initializer", "/versions/12/facts/5/label": "Memory mechanism", "/versions/12/tables/0/title": "EXPLAIN labels in this source build", "/versions/12/related/1/label": "Using EXPLAIN", "/versions/12/related/2/label": "Parallel plans", "/versions/12/sections/0/title": "EXPLAIN names and attributes", "/versions/12/sections/1/title": "Memory and temporary storage", "/versions/12/sections/2/title": "Parallel execution and instrumentation", "/versions/12/sections/3/title": "Executor implementation notes", "/versions/12/sections/4/title": "EXPLAIN identity in core source", "/versions/12/memory/description": "This 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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/12/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/12/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/12/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/12/sections/3/paragraphs/4": "Scans the subquery sequentially and returns the next qualifying tuple. 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"src/backend/executor/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "a97d270f24122ea18316fa70621fb7401286171a6ddac0869d87262f0f110bb0", "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"}], "node_tag": "T_SubqueryScan", "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\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/14/description/0": "Scans the output of a subquery plan.", "/versions/14/facts/0/label": "Core node tag", "/versions/14/facts/1/label": "Structured EXPLAIN Node Type", "/versions/14/facts/2/label": "Inputs", "/versions/14/facts/2/value": "A subquery child plan", "/versions/14/facts/3/label": "Output", "/versions/14/facts/3/value": "Subquery result tuples", "/versions/14/facts/4/label": "Executor initializer", "/versions/14/facts/5/label": "Memory mechanism", "/versions/14/tables/0/title": "EXPLAIN labels in this source build", "/versions/14/related/1/label": "Using EXPLAIN", "/versions/14/related/2/label": "Parallel plans", "/versions/14/sections/0/title": "EXPLAIN names and attributes", "/versions/14/sections/1/title": "Memory and temporary storage", "/versions/14/sections/2/title": "Parallel execution and instrumentation", "/versions/14/sections/3/title": "Executor implementation notes", "/versions/14/sections/4/title": "EXPLAIN identity in core source", "/versions/14/memory/description": "This 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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/14/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/14/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/14/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/14/sections/3/paragraphs/4": "Scans the subquery 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": "70d5cd6b78138eb88c475d29166123159d551680b05cd347aea4faeada9a8c60"}, "evidence_kind": "source and documentation", "explain_names": ["Subquery Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_SubqueryScan", "strategies": [], "text_names": ["Subquery Scan"], "initializer": "ExecInitSubqueryScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "2c67fdef6b55d5dfeedc05274c332f8e523a7b8dd3ffef1c7cb79b9d6d33566f", "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/nodeSubqueryscan.c"}, "parallel_callbacks": []}, "15": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SubqueryScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Subquery Scan"}, {"label": "\u8f93\u5165", "value": "\u5b50\u67e5\u8be2\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u5b50\u67e5\u8be2\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSubqueryScan"}, {"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/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "c376ce0867d8ff0b16c5c37da98620181842383c41ec56e2cccafe3dc72ba267", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}], "mechanism": "unclassified", "description": "\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", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Subquery Scan", "identity": "Subquery 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": 1255, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1255", "sha256": "bb3b442d0f1b098aa8707335250102f027a596cd94117308bd16d1d36b258f5c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "line": 249, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:249", "sha256": "19836c50a272741a4eac653541e655437c2e00710a541e5348d6a277d0669d7c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "c376ce0867d8ff0b16c5c37da98620181842383c41ec56e2cccafe3dc72ba267", "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"}], "node_tag": "T_SubqueryScan", "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\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/15/description/0": "Scans the output of a subquery plan.", "/versions/15/facts/0/label": "Core node tag", "/versions/15/facts/1/label": "Structured EXPLAIN Node Type", "/versions/15/facts/2/label": "Inputs", "/versions/15/facts/2/value": "A subquery child plan", "/versions/15/facts/3/label": "Output", "/versions/15/facts/3/value": "Subquery result tuples", "/versions/15/facts/4/label": "Executor initializer", "/versions/15/facts/5/label": "Memory mechanism", "/versions/15/tables/0/title": "EXPLAIN labels in this source build", "/versions/15/related/1/label": "Using EXPLAIN", "/versions/15/related/2/label": "Parallel plans", "/versions/15/sections/0/title": "EXPLAIN names and attributes", "/versions/15/sections/1/title": "Memory and temporary storage", "/versions/15/sections/2/title": "Parallel execution and instrumentation", "/versions/15/sections/3/title": "Executor implementation notes", "/versions/15/sections/4/title": "EXPLAIN identity in core source", "/versions/15/memory/description": "This 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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/15/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/15/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/15/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/15/sections/3/paragraphs/4": "Scans the subquery sequentially and returns the next qualifying tuple. 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"src/backend/executor/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "3ce294038952ff3960bbfb30d1f2cfa89c04b3bc5014587a1f58107f3d629634", "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"}], "node_tag": "T_SubqueryScan", "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\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/17/description/0": "Scans the output of a subquery plan.", "/versions/17/facts/0/label": "Core node tag", "/versions/17/facts/1/label": "Structured EXPLAIN Node Type", "/versions/17/facts/2/label": "Inputs", "/versions/17/facts/2/value": "A subquery child plan", "/versions/17/facts/3/label": "Output", "/versions/17/facts/3/value": "Subquery result tuples", "/versions/17/facts/4/label": "Executor initializer", "/versions/17/facts/5/label": "Memory mechanism", "/versions/17/tables/0/title": "EXPLAIN labels in this source build", "/versions/17/related/1/label": "Using EXPLAIN", "/versions/17/related/2/label": "Parallel plans", "/versions/17/sections/0/title": "EXPLAIN names and attributes", "/versions/17/sections/1/title": "Memory and temporary storage", "/versions/17/sections/2/title": "Parallel execution and instrumentation", "/versions/17/sections/3/title": "Executor implementation notes", "/versions/17/sections/4/title": "EXPLAIN identity in core source", "/versions/17/memory/description": "This 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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/17/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/17/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/17/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/17/sections/3/paragraphs/4": "Scans the subquery 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": "c5fa86a414617898c5e4e61a10956ca1efc3bdd84b8abe2a8de420ba380a3ee0"}, "evidence_kind": "source and documentation", "explain_names": ["Subquery Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_SubqueryScan", "strategies": [], "text_names": ["Subquery Scan"], "initializer": "ExecInitSubqueryScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "2c67fdef6b55d5dfeedc05274c332f8e523a7b8dd3ffef1c7cb79b9d6d33566f", "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/nodeSubqueryscan.c"}, "parallel_callbacks": []}, "18": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SubqueryScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Subquery Scan"}, {"label": "\u8f93\u5165", "value": "\u5b50\u67e5\u8be2\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u5b50\u67e5\u8be2\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSubqueryScan"}, {"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/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "9e5a1653e5b1678c457026f940a36bb2927cbfb1fa1f6a6a296e1bd1453ef29b", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "mechanism": "unclassified", "description": "\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", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Subquery Scan", "identity": "Subquery 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": 1462, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1462", "sha256": "34c86d6070224a0e981efef51f79101d6d505e5874f1684ace183034bab14bb4", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 249, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:249", "sha256": "f8a06a3f539077249b20664b2812433db6d7bd12b2c0ca633525db43d06f112a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "9e5a1653e5b1678c457026f940a36bb2927cbfb1fa1f6a6a296e1bd1453ef29b", "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"}], "node_tag": "T_SubqueryScan", "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\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Scans the output of a subquery plan.", "/versions/18/facts/0/label": "Core node tag", "/versions/18/facts/1/label": "Structured EXPLAIN Node Type", "/versions/18/facts/2/label": "Inputs", "/versions/18/facts/2/value": "A subquery child plan", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Subquery result tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/tables/0/title": "EXPLAIN labels in this source build", "/versions/18/related/1/label": "Using EXPLAIN", "/versions/18/related/2/label": "Parallel plans", "/versions/18/sections/0/title": "EXPLAIN names and attributes", "/versions/18/sections/1/title": "Memory and temporary storage", "/versions/18/sections/2/title": "Parallel execution and instrumentation", "/versions/18/sections/3/title": "Executor implementation notes", "/versions/18/sections/4/title": "EXPLAIN identity in core source", "/versions/18/memory/description": "This 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: Subquery 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. 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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\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/summary": "Scans the output of a subquery plan.", "/category": "Scan", "/versions/20/description/0": "Scans the output of a subquery plan.", "/versions/20/facts/0/label": "Core node tag", "/versions/20/facts/1/label": "Structured EXPLAIN Node Type", "/versions/20/facts/2/label": "Inputs", "/versions/20/facts/2/value": "A subquery child plan", "/versions/20/facts/3/label": "Output", "/versions/20/facts/3/value": "Subquery result tuples", "/versions/20/facts/4/label": "Executor initializer", "/versions/20/facts/5/label": "Memory mechanism", "/versions/20/tables/0/title": "EXPLAIN labels in this source build", "/versions/20/related/1/label": "Using EXPLAIN", "/versions/20/related/2/label": "Parallel plans", "/versions/20/sections/0/title": "EXPLAIN names and attributes", "/versions/20/sections/1/title": "Memory and temporary storage", "/versions/20/sections/2/title": "Parallel execution and instrumentation", "/versions/20/sections/3/title": "Executor implementation notes", "/versions/20/sections/4/title": "EXPLAIN identity in core source", "/versions/20/memory/description": "This 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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/20/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/20/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/20/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/20/sections/3/paragraphs/4": "Scans the subquery 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": "798390408590bd819587132c2fc7d4200ebb2d8b0aa9dd80bfcb8b829880411f"}, "evidence_kind": "source and documentation", "explain_names": ["Subquery Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_SubqueryScan", "strategies": [], "text_names": ["Subquery Scan"], "initializer": "ExecInitSubqueryScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "2c67fdef6b55d5dfeedc05274c332f8e523a7b8dd3ffef1c7cb79b9d6d33566f", "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/nodeSubqueryscan.c"}, "parallel_callbacks": []}}}, "snapshot": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SubqueryScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Subquery Scan"}, {"label": "\u8f93\u5165", "value": "\u5b50\u67e5\u8be2\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u5b50\u67e5\u8be2\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSubqueryScan"}, {"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/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "9e5a1653e5b1678c457026f940a36bb2927cbfb1fa1f6a6a296e1bd1453ef29b", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "mechanism": "unclassified", "description": "\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", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Subquery Scan", "identity": "Subquery 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": 1462, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1462", "sha256": "34c86d6070224a0e981efef51f79101d6d505e5874f1684ace183034bab14bb4", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 249, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:249", "sha256": "f8a06a3f539077249b20664b2812433db6d7bd12b2c0ca633525db43d06f112a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeSubqueryscan.c", "label": "src/backend/executor/nodeSubqueryscan.c", "sha256": "9e5a1653e5b1678c457026f940a36bb2927cbfb1fa1f6a6a296e1bd1453ef29b", "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"}], "node_tag": "T_SubqueryScan", "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\uff1aSubquery 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": ["nodeSubqueryscan.c\uff1a\u652f\u6301\u626b\u63cf\u5b50\u67e5\u8be2\uff08\u8303\u56f4\u8868\u4e2d\u7684\u5b50 SELECT\uff09\u7684\u4f8b\u7a0b\u3002", "\u8fd9\u4e0e\u5b50\u94fe\u63a5\uff08nodeSubplan.c\uff09\u7a0d\u6709\u5dee\u522b\uff0c\u56e0\u6b64\u9700\u8981\u4e24\u5957\u4ee3\u7801\u3002\u5e94\u8003\u8651\u5c1d\u8bd5\u5c06\u8fd9\u4e9b\u60c5\u51b5\u7edf\u4e00\u3002", "\u76f4\u63a5\u8fd4\u56de\u5b50\u8ba1\u5212\u7684\u7ed3\u679c\u69fd\u4f4d\uff0c\u907f\u514d ExecCopySlot() \u7684\u989d\u5916\u5f00\u9500\u3002\uff08\u8282\u70b9\u81ea\u8eab\u7684 ScanTupleSlot \u4ec5\u7528\u4e8e EvalPlanQual \u91cd\u65b0\u68c0\u67e5\u3002\uff09", "SubqueryRecheck\uff1a\u5728 EvalPlanQual \u4e2d\u91cd\u65b0\u68c0\u67e5\u5143\u7ec4\u7684\u8bbf\u95ee\u65b9\u6cd5\u4f8b\u7a0b\u3002", "\u987a\u5e8f\u626b\u63cf\u5b50\u67e5\u8be2\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_SubqueryScan:\n\t\t\tpname = sname = \"Subquery Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u626b\u63cf\u5b50\u67e5\u8be2\u8ba1\u5212\u7684\u8f93\u51fa\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Scans the output of a subquery plan.", "/versions/18/facts/0/label": "Core node tag", "/versions/18/facts/1/label": "Structured EXPLAIN Node Type", "/versions/18/facts/2/label": "Inputs", "/versions/18/facts/2/value": "A subquery child plan", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Subquery result tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/tables/0/title": "EXPLAIN labels in this source build", "/versions/18/related/1/label": "Using EXPLAIN", "/versions/18/related/2/label": "Parallel plans", "/versions/18/sections/0/title": "EXPLAIN names and attributes", "/versions/18/sections/1/title": "Memory and temporary storage", "/versions/18/sections/2/title": "Parallel execution and instrumentation", "/versions/18/sections/3/title": "Executor implementation notes", "/versions/18/sections/4/title": "EXPLAIN identity in core source", "/versions/18/memory/description": "This 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: Subquery 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": "nodeSubqueryscan.c Support routines for scanning subqueries (subselects in rangetable).", "/versions/18/sections/3/paragraphs/1": "This is just enough different from sublinks (nodeSubplan.c) to mean that we need two sets of code. Ought to look at trying to unify the cases.", "/versions/18/sections/3/paragraphs/2": "We just return the subplan's result slot, rather than expending extra cycles for ExecCopySlot(). (Our own ScanTupleSlot is used only for EvalPlanQual rechecks.)", "/versions/18/sections/3/paragraphs/3": "SubqueryRecheck -- access method routine to recheck a tuple in EvalPlanQual", "/versions/18/sections/3/paragraphs/4": "Scans the subquery 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": "69301e70f0200d5845e679ff940a2d05cc2ab7e7c6ac58394fa39691e17c321e"}, "evidence_kind": "source and documentation", "explain_names": ["Subquery Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_SubqueryScan", "strategies": [], "text_names": ["Subquery Scan"], "initializer": "ExecInitSubqueryScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "2c67fdef6b55d5dfeedc05274c332f8e523a7b8dd3ffef1c7cb79b9d6d33566f", "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/nodeSubqueryscan.c"}, "parallel_callbacks": []}, "comparison": {"left": "17", "right": "18", "status": "unchanged", "diff": ""}}