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\u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u8fd8\u6309\u6240\u6709\u5206\u7ec4\u5217\uff08\u5373\u6240\u6709\u975e\u8f85\u52a9\u5c5e\u6027\uff09\u6392\u5e8f\u3002SetOp \u626b\u63cf\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\uff0c\u786e\u5b9a\u5404\u8f93\u5165\u5173\u7cfb\u5206\u522b\u8d21\u732e\u4e86\u591a\u5c11\u4e2a\uff0c\u7136\u540e\u6309 SQL \u89c4\u8303\u8f93\u51fa INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8981\u6c42\u7684\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\uff0c\u4f46\u5df2\u77e5\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u6240\u6709\u5143\u7ec4\u90fd\u5148\u4e8e\u53e6\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u5168\u90e8\u5143\u7ec4\u5230\u8fbe\u3002\u5bf9\u4e8e EXCEPT\uff0c\u89c4\u5212\u5668\u4fdd\u8bc1\u5de6\u4fa7\u5173\u7cfb\u5148\u8f93\u5165\uff1b\u5bf9\u4e8e INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/10/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/10/facts/3/label": "Output", "/versions/10/facts/3/value": "Set-operation result tuples", "/versions/10/facts/4/label": "Executor initializer", "/versions/10/facts/5/label": "Memory mechanism", "/versions/10/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/10/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/10/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/10/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/10/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "e611165815a9578dfeb9c50e59243139efaa05cac66e20fef612711ca0d65635"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "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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"https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "f0f13f44a8a9173dc2f3c6ae4db7d61a5e2ec7a60cc17a669eaaf946db39137f", "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"}], "node_tag": "T_SetOp", "sections": [{"title": "EXPLAIN \u540d\u79f0\u4e0e\u5c5e\u6027", "paragraphs": ["\u7ed3\u6784\u5316\u683c\u5f0f\u4f7f\u7528\u4e0a\u8ff0 Node 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"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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED 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INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/11/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/11/facts/3/label": "Output", "/versions/11/facts/3/value": "Set-operation result tuples", "/versions/11/facts/4/label": "Executor initializer", "/versions/11/facts/5/label": "Memory mechanism", "/versions/11/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/11/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/11/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/11/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/11/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "6168943e8694ec43c395c01c0ee251728f0b772f07f2495be6dce0a0c015e97d"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "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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"https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "7d6283985a698d0632f4253fb43841e19606db8445c295789ced49c35846e084", "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_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u8fd8\u6309\u6240\u6709\u5206\u7ec4\u5217\uff08\u5373\u6240\u6709\u975e\u8f85\u52a9\u5c5e\u6027\uff09\u6392\u5e8f\u3002SetOp \u626b\u63cf\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\uff0c\u786e\u5b9a\u5404\u8f93\u5165\u5173\u7cfb\u5206\u522b\u8d21\u732e\u4e86\u591a\u5c11\u4e2a\uff0c\u7136\u540e\u6309 SQL \u89c4\u8303\u8f93\u51fa INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8981\u6c42\u7684\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\uff0c\u4f46\u5df2\u77e5\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u6240\u6709\u5143\u7ec4\u90fd\u5148\u4e8e\u53e6\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u5168\u90e8\u5143\u7ec4\u5230\u8fbe\u3002\u5bf9\u4e8e EXCEPT\uff0c\u89c4\u5212\u5668\u4fdd\u8bc1\u5de6\u4fa7\u5173\u7cfb\u5148\u8f93\u5165\uff1b\u5bf9\u4e8e INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/12/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/12/facts/3/label": "Output", "/versions/12/facts/3/value": "Set-operation result tuples", "/versions/12/facts/4/label": "Executor initializer", "/versions/12/facts/5/label": "Memory mechanism", "/versions/12/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/12/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/12/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/12/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/12/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "b479af451f0a0114d2be857e04cdbf84a6dc3a38c12bfe98b6f2324b3edd1a1e"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeSetOp.c"}, "parallel_callbacks": []}, "13": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SetOp"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "SetOp"}, {"label": "\u8f93\u5165", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u8f93\u5165\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSetOp"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}, {"label": "EXPLAIN \u7b56\u7565", "value": "Sorted, Hashed"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "294b1db70acfa830bd48ace47cad55791b10264fd34d3c21315fb83071cb1d51", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}], "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": "SetOp", "identity": "SetOp"}, {"label": "HashSetOp", "identity": "SetOp"}], "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": 1328, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1328", "sha256": "541713e0e7f1c9cc352c2b6028964d440c19d2678a4463000094c24a88c1e730", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "line": 358, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:358", "sha256": "d085ee99acfa00587e6ade3a1d9f8108a0566beedbbee3f54a50c9fc0cc2e875", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "294b1db70acfa830bd48ace47cad55791b10264fd34d3c21315fb83071cb1d51", "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"}], "node_tag": "T_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u8fd8\u6309\u6240\u6709\u5206\u7ec4\u5217\uff08\u5373\u6240\u6709\u975e\u8f85\u52a9\u5c5e\u6027\uff09\u6392\u5e8f\u3002SetOp \u626b\u63cf\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\uff0c\u786e\u5b9a\u5404\u8f93\u5165\u5173\u7cfb\u5206\u522b\u8d21\u732e\u4e86\u591a\u5c11\u4e2a\uff0c\u7136\u540e\u6309 SQL \u89c4\u8303\u8f93\u51fa INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8981\u6c42\u7684\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\uff0c\u4f46\u5df2\u77e5\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u6240\u6709\u5143\u7ec4\u90fd\u5148\u4e8e\u53e6\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u5168\u90e8\u5143\u7ec4\u5230\u8fbe\u3002\u5bf9\u4e8e EXCEPT\uff0c\u89c4\u5212\u5668\u4fdd\u8bc1\u5de6\u4fa7\u5173\u7cfb\u5148\u8f93\u5165\uff1b\u5bf9\u4e8e INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/13/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/13/facts/3/label": "Output", "/versions/13/facts/3/value": "Set-operation result tuples", "/versions/13/facts/4/label": "Executor initializer", "/versions/13/facts/5/label": "Memory mechanism", "/versions/13/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/13/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/13/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/13/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/13/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "64879327c59c673c9ab4ff7125dd6b7a86ac9a074af003d9df679811a6d248e0"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeSetOp.c"}, "parallel_callbacks": []}, "14": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SetOp"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "SetOp"}, {"label": "\u8f93\u5165", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u8f93\u5165\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSetOp"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}, {"label": "EXPLAIN \u7b56\u7565", "value": "Sorted, Hashed"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "20c09781e6272d6e851c4c1f135bdc4e918a66b8f864247dea904506179581fe", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}], "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": "SetOp", "identity": "SetOp"}, {"label": "HashSetOp", "identity": "SetOp"}], "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": 1370, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1370", "sha256": "e091be4e2a083b8dea39ccd09beedede22c1716ef974da66c214a44f48be8c41", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "line": 370, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:370", "sha256": "72da1c5ad457f1d92a39ab73531701794df858419e3b89d6e6cb7079634e68fa", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "20c09781e6272d6e851c4c1f135bdc4e918a66b8f864247dea904506179581fe", "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_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u8fd8\u6309\u6240\u6709\u5206\u7ec4\u5217\uff08\u5373\u6240\u6709\u975e\u8f85\u52a9\u5c5e\u6027\uff09\u6392\u5e8f\u3002SetOp \u626b\u63cf\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\uff0c\u786e\u5b9a\u5404\u8f93\u5165\u5173\u7cfb\u5206\u522b\u8d21\u732e\u4e86\u591a\u5c11\u4e2a\uff0c\u7136\u540e\u6309 SQL \u89c4\u8303\u8f93\u51fa INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8981\u6c42\u7684\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\uff0c\u4f46\u5df2\u77e5\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u6240\u6709\u5143\u7ec4\u90fd\u5148\u4e8e\u53e6\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u5168\u90e8\u5143\u7ec4\u5230\u8fbe\u3002\u5bf9\u4e8e EXCEPT\uff0c\u89c4\u5212\u5668\u4fdd\u8bc1\u5de6\u4fa7\u5173\u7cfb\u5148\u8f93\u5165\uff1b\u5bf9\u4e8e INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/14/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/14/facts/3/label": "Output", "/versions/14/facts/3/value": "Set-operation result tuples", "/versions/14/facts/4/label": "Executor initializer", "/versions/14/facts/5/label": "Memory mechanism", "/versions/14/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/14/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/14/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/14/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/14/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "b4b5b7fea581867b316268bfa2ae66c320135d65357b59da3a8cf3e50cdcadad"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "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/nodeSetOp.c"}, "parallel_callbacks": []}, "15": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SetOp"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "SetOp"}, {"label": "\u8f93\u5165", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u8f93\u5165\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSetOp"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}, {"label": "EXPLAIN \u7b56\u7565", "value": "Sorted, Hashed"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "811181891ce2ebff2b23a943e024707ea638674acf56bb570371323dcef194ed", "archive_sha256": 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{"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": 1373, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1373", "sha256": "bb3b442d0f1b098aa8707335250102f027a596cd94117308bd16d1d36b258f5c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "line": 370, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:370", "sha256": "19836c50a272741a4eac653541e655437c2e00710a541e5348d6a277d0669d7c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "811181891ce2ebff2b23a943e024707ea638674acf56bb570371323dcef194ed", "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_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u8fd8\u6309\u6240\u6709\u5206\u7ec4\u5217\uff08\u5373\u6240\u6709\u975e\u8f85\u52a9\u5c5e\u6027\uff09\u6392\u5e8f\u3002SetOp \u626b\u63cf\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\uff0c\u786e\u5b9a\u5404\u8f93\u5165\u5173\u7cfb\u5206\u522b\u8d21\u732e\u4e86\u591a\u5c11\u4e2a\uff0c\u7136\u540e\u6309 SQL \u89c4\u8303\u8f93\u51fa INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8981\u6c42\u7684\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\uff0c\u4f46\u5df2\u77e5\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u6240\u6709\u5143\u7ec4\u90fd\u5148\u4e8e\u53e6\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u5168\u90e8\u5143\u7ec4\u5230\u8fbe\u3002\u5bf9\u4e8e EXCEPT\uff0c\u89c4\u5212\u5668\u4fdd\u8bc1\u5de6\u4fa7\u5173\u7cfb\u5148\u8f93\u5165\uff1b\u5bf9\u4e8e INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/15/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/15/facts/3/label": "Output", "/versions/15/facts/3/value": "Set-operation result tuples", "/versions/15/facts/4/label": "Executor initializer", "/versions/15/facts/5/label": "Memory mechanism", "/versions/15/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/15/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/15/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/15/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/15/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "799e919e06ee41cc242eee29f9d0e89fe74894e04e2c92df52ea91ca84543b9a"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "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/nodeSetOp.c"}, "parallel_callbacks": []}, "16": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SetOp"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "SetOp"}, {"label": "\u8f93\u5165", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u8f93\u5165\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSetOp"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}, {"label": "EXPLAIN \u7b56\u7565", "value": "Sorted, Hashed"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "1d5d7dabf9ec58223c24f2933ecac0f5127ade4e7d170ca7a4477207c6ce6aa8", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}], "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": "SetOp", "identity": "SetOp"}, {"label": "HashSetOp", "identity": "SetOp"}], "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": 1406, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1406", "sha256": "8e017f0116dbea471339b40c37a667cc9f95039e7e0329c783e5e8ce194de7e1", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "line": 370, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:370", "sha256": "e48c08e555f8cb4e4bb43df516c4b8906ce9bc374b2a745d98a1fc8c22cc5099", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "1d5d7dabf9ec58223c24f2933ecac0f5127ade4e7d170ca7a4477207c6ce6aa8", "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"}], "node_tag": "T_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u8fd8\u6309\u6240\u6709\u5206\u7ec4\u5217\uff08\u5373\u6240\u6709\u975e\u8f85\u52a9\u5c5e\u6027\uff09\u6392\u5e8f\u3002SetOp \u626b\u63cf\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\uff0c\u786e\u5b9a\u5404\u8f93\u5165\u5173\u7cfb\u5206\u522b\u8d21\u732e\u4e86\u591a\u5c11\u4e2a\uff0c\u7136\u540e\u6309 SQL \u89c4\u8303\u8f93\u51fa INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8981\u6c42\u7684\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\uff0c\u4f46\u5df2\u77e5\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u6240\u6709\u5143\u7ec4\u90fd\u5148\u4e8e\u53e6\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u5168\u90e8\u5143\u7ec4\u5230\u8fbe\u3002\u5bf9\u4e8e EXCEPT\uff0c\u89c4\u5212\u5668\u4fdd\u8bc1\u5de6\u4fa7\u5173\u7cfb\u5148\u8f93\u5165\uff1b\u5bf9\u4e8e INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/16/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/16/facts/3/label": "Output", "/versions/16/facts/3/value": "Set-operation result tuples", "/versions/16/facts/4/label": "Executor initializer", "/versions/16/facts/5/label": "Memory mechanism", "/versions/16/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/16/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/16/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/16/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/16/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "833edc423df6550acbeef7f9fa465466e2cb2b5604453971e979b5d7ba6f9c9e"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "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/nodeSetOp.c"}, "parallel_callbacks": []}, "17": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SetOp"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "SetOp"}, {"label": "\u8f93\u5165", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u8f93\u5165\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSetOp"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}, {"label": "EXPLAIN \u7b56\u7565", "value": "Sorted, Hashed"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "dae884715d1b9062dde74bda9cbefbdef50a93fd73a4a42df56123a9e165f014", "archive_sha256": 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"dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, {"url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "dae884715d1b9062dde74bda9cbefbdef50a93fd73a4a42df56123a9e165f014", "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_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u662f\u6765\u81ea\u4e24\u4e2a\u5173\u7cfb\u3001\u5408\u5e76\u5230\u540c\u4e00\u6570\u636e\u96c6\u7684\u5143\u7ec4\uff0c\u5e76\u6dfb\u52a0\u4e00\u4e2a\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6bcf\u4e2a\u5143\u7ec4\u7684\u6765\u6e90\u5173\u7cfb\u3002\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u8fd8\u6309\u6240\u6709\u5206\u7ec4\u5217\uff08\u5373\u6240\u6709\u975e\u8f85\u52a9\u5c5e\u6027\uff09\u6392\u5e8f\u3002SetOp \u626b\u63cf\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\uff0c\u786e\u5b9a\u5404\u8f93\u5165\u5173\u7cfb\u5206\u522b\u8d21\u732e\u4e86\u591a\u5c11\u4e2a\uff0c\u7136\u540e\u6309 SQL \u89c4\u8303\u8f93\u51fa INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8981\u6c42\u7684\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\uff0c\u4f46\u5df2\u77e5\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u6240\u6709\u5143\u7ec4\u90fd\u5148\u4e8e\u53e6\u4e00\u4e2a\u8f93\u5165\u5173\u7cfb\u7684\u5168\u90e8\u5143\u7ec4\u5230\u8fbe\u3002\u5bf9\u4e8e EXCEPT\uff0c\u89c4\u5212\u5668\u4fdd\u8bc1\u5de6\u4fa7\u5173\u7cfb\u5148\u8f93\u5165\uff1b\u5bf9\u4e8e INTERSECT\uff0c\u5219\u5c3d\u91cf\u8ba9\u8f83\u5c0f\u7684\u5173\u7cfb\u5148\u8f93\u5165\u3002\u6211\u4eec\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u5206\u522b\u7edf\u8ba1\u5404\u5173\u7cfb\u5728\u8be5\u7ec4\u4e2d\u7684\u5143\u7ec4\u6570\u91cf\u3002\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002\u4ec5\u51fa\u73b0\u5728\u7b2c\u4e8c\u4e2a\u8f93\u5165\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u65e0\u9700\u4e3a\u5b83\u4eec\u5efa\u7acb\u54c8\u5e0c\u8868\u6761\u76ee\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u8f85\u52a9\u5c5e\u6027\u6765\u6807\u8bc6\u6765\u6e90\u5173\u7cfb\u3002", "SetOp \u4e0d\u68c0\u67e5\u7b5b\u9009\u6761\u4ef6\uff0c\u4e5f\u4e0d\u6267\u884c\u6295\u5f71\u3002\u8f93\u51fa\u5143\u7ec4\u53ea\u662f\u6bcf\u4e2a\u8f93\u5165\u7ec4\u4e2d\u6700\u5148\u5230\u8fbe\u7684\u5143\u7ec4\u7684\u526f\u672c\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/17/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/17/facts/3/label": "Output", "/versions/17/facts/3/value": "Set-operation result tuples", "/versions/17/facts/4/label": "Executor initializer", "/versions/17/facts/5/label": "Memory mechanism", "/versions/17/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/17/sections/3/paragraphs/1": "The input of a SetOp node consists of tuples from two relations, which have been combined into one dataset, with a junk attribute added that shows which relation each tuple came from. In SETOP_SORTED mode, the input has furthermore been sorted according to all the grouping columns (ie, all the non-junk attributes). The SetOp node scans each group of identical tuples to determine how many came from each input relation. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/17/sections/3/paragraphs/2": "In SETOP_HASHED mode, the input is delivered in no particular order, except that we know all the tuples from one input relation will come before all the tuples of the other. The planner guarantees that the first input relation is the left-hand one for EXCEPT, and tries to make the smaller input relation come first for INTERSECT. We build a hash table in memory with one entry for each group of identical tuples, and count the number of tuples in the group from each relation. After seeing all the input, we scan the hashtable and generate the correct output using those counts. We can avoid making hashtable entries for any tuples appearing only in the second input relation, since they cannot result in any output.", "/versions/17/sections/3/paragraphs/3": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need for the junk attribute to identify the source relation).", "/versions/17/sections/3/paragraphs/4": "Note that SetOp does no qual checking nor projection. The delivered output tuples are just copies of the first-to-arrive tuple in each input group.", "/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": "e5038b1d545d633c441461017633356747c1b6948db1ca6a7947687d76d9dc35"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", 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"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "337c8a4ab549bd36155243da4f71384647d63b6475bb548f6fcdfd1a663bd8a7", "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_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u4e3a\u5217\u96c6\u5408\u5b8c\u5168\u76f8\u540c\u7684\u4e24\u4e2a\u5173\u7cfb\uff08\u5916\u4fa7\u548c\u5185\u4fa7\uff09\u3002EXCEPT \u67e5\u8be2\u4e2d\uff0c\u5916\u4fa7\u59cb\u7ec8\u662f\u5de6\u4fa7\u5173\u7cfb\uff1bINTERSECT \u4e2d\uff0c\u89c4\u5212\u5668\u5c3d\u91cf\u628a\u8f83\u5c0f\u7684\u8f93\u5165\u653e\u5728\u5916\u4fa7\u3002", "\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u5404\u8f93\u5165\u90fd\u5df2\u6309\u5168\u90e8\u5206\u7ec4\u5217\u6392\u5e8f\u3002SetOp \u8282\u70b9\u672c\u8d28\u4e0a\u6309\u5206\u7ec4\u5217\u6267\u884c\u5f52\u5e76\u8fde\u63a5\uff0c\u4f46\u53ea\u5173\u5fc3\u5404\u8f93\u5165\u6709\u591a\u5c11\u5143\u7ec4\u5339\u914d\u3002\u968f\u540e\u4fbf\u53ef\u6839\u636e SQL \u89c4\u8303\uff0c\u4e3a INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8f93\u51fa\u76f8\u5e94\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\u3002\u5148\u8bfb\u53d6\u5916\u4fa7\u5173\u7cfb\uff0c\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u7edf\u8ba1\u7ec4\u5185\u5143\u7ec4\u6570\u91cf\uff1b\u518d\u8bfb\u53d6\u5185\u4fa7\u5173\u7cfb\uff0c\u7edf\u8ba1\u4e0e\u6bcf\u4e2a\u5916\u4fa7\u5206\u7ec4\u5339\u914d\u7684\u5143\u7ec4\u6570\u91cf\u3002\uff08\u4ec5\u51fa\u73b0\u5728\u5185\u4fa7\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u53ef\u4ee5\u5ffd\u7565\u3002\uff09\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u7edf\u8ba1\u5339\u914d\u5143\u7ec4\u6570\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Set-operation result tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/18/sections/3/paragraphs/1": "The input of a SetOp node consists of two relations (outer and inner) with identical column sets. In EXCEPT queries the outer relation is always the left side, while in INTERSECT cases the planner tries to make the outer relation be the smaller of the two inputs.", "/versions/18/sections/3/paragraphs/2": "In SETOP_SORTED mode, each input has been sorted according to all the grouping columns. The SetOp node essentially performs a merge join on the grouping columns, except that it is only interested in counting how many tuples from each input match. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/18/sections/3/paragraphs/3": "In SETOP_HASHED mode, the inputs are delivered in no particular order. We read the outer relation and build a hash table in memory with one entry for each group of identical tuples, counting the number of tuples in the group. Then we read the inner relation and count the number of tuples matching each outer group. (We can disregard any tuples appearing only in the inner relation, since they cannot result in any output.) After seeing all the input, we scan the hashtable and generate the correct output using those counts.", "/versions/18/sections/3/paragraphs/4": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need to count the number of matching tuples).", "/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": "5dd747fc04583ea4741bd028a3f97ba26271be497748f8877b6e7314162148b1"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": 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"83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}], "node_tag": "T_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u4e3a\u5217\u96c6\u5408\u5b8c\u5168\u76f8\u540c\u7684\u4e24\u4e2a\u5173\u7cfb\uff08\u5916\u4fa7\u548c\u5185\u4fa7\uff09\u3002EXCEPT \u67e5\u8be2\u4e2d\uff0c\u5916\u4fa7\u59cb\u7ec8\u662f\u5de6\u4fa7\u5173\u7cfb\uff1bINTERSECT \u4e2d\uff0c\u89c4\u5212\u5668\u5c3d\u91cf\u628a\u8f83\u5c0f\u7684\u8f93\u5165\u653e\u5728\u5916\u4fa7\u3002", "\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u5404\u8f93\u5165\u90fd\u5df2\u6309\u5168\u90e8\u5206\u7ec4\u5217\u6392\u5e8f\u3002SetOp \u8282\u70b9\u672c\u8d28\u4e0a\u6309\u5206\u7ec4\u5217\u6267\u884c\u5f52\u5e76\u8fde\u63a5\uff0c\u4f46\u53ea\u5173\u5fc3\u5404\u8f93\u5165\u6709\u591a\u5c11\u5143\u7ec4\u5339\u914d\u3002\u968f\u540e\u4fbf\u53ef\u6839\u636e SQL \u89c4\u8303\uff0c\u4e3a INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8f93\u51fa\u76f8\u5e94\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\u3002\u5148\u8bfb\u53d6\u5916\u4fa7\u5173\u7cfb\uff0c\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u7edf\u8ba1\u7ec4\u5185\u5143\u7ec4\u6570\u91cf\uff1b\u518d\u8bfb\u53d6\u5185\u4fa7\u5173\u7cfb\uff0c\u7edf\u8ba1\u4e0e\u6bcf\u4e2a\u5916\u4fa7\u5206\u7ec4\u5339\u914d\u7684\u5143\u7ec4\u6570\u91cf\u3002\uff08\u4ec5\u51fa\u73b0\u5728\u5185\u4fa7\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u53ef\u4ee5\u5ffd\u7565\u3002\uff09\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u7edf\u8ba1\u5339\u914d\u5143\u7ec4\u6570\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/19/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/19/facts/3/label": "Output", "/versions/19/facts/3/value": "Set-operation result tuples", "/versions/19/facts/4/label": "Executor initializer", "/versions/19/facts/5/label": "Memory mechanism", "/versions/19/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/19/sections/3/paragraphs/1": "The input of a SetOp node consists of two relations (outer and inner) with identical column sets. In EXCEPT queries the outer relation is always the left side, while in INTERSECT cases the planner tries to make the outer relation be the smaller of the two inputs.", "/versions/19/sections/3/paragraphs/2": "In SETOP_SORTED mode, each input has been sorted according to all the grouping columns. The SetOp node essentially performs a merge join on the grouping columns, except that it is only interested in counting how many tuples from each input match. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/19/sections/3/paragraphs/3": "In SETOP_HASHED mode, the inputs are delivered in no particular order. We read the outer relation and build a hash table in memory with one entry for each group of identical tuples, counting the number of tuples in the group. Then we read the inner relation and count the number of tuples matching each outer group. (We can disregard any tuples appearing only in the inner relation, since they cannot result in any output.) After seeing all the input, we scan the hashtable and generate the correct output using those counts.", "/versions/19/sections/3/paragraphs/4": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need to count the number of matching tuples).", "/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": "73bd188eef33ef5c21bde161c4dde74f208c0787b97a191ae321c3800e35ffa3"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "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/nodeSetOp.c"}, "parallel_callbacks": []}, "20": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_SetOp"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "SetOp"}, {"label": "\u8f93\u5165", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u8f93\u5165\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u96c6\u5408\u64cd\u4f5c\u7684\u7ed3\u679c\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitSetOp"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}, {"label": "EXPLAIN \u7b56\u7565", "value": "Sorted, Hashed"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "11d3630196d35576ca9f9a50a61946b82338de3e8871147f6cf2cb0456e70d14", "archive_sha256": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41"}], "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": "SetOp", "identity": "SetOp"}, {"label": "HashSetOp", "identity": "SetOp"}], "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": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41", "source_url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "source_snapshot_utc": "26-Sep-2026 20:22"}, "sources": [{"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "line": 1592, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1592", "sha256": "13402758013520451539427b5993db06d463ca11c4e2d4cc5444e82367688077", "archive_sha256": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41"}, {"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "line": 370, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:370", "sha256": "5e39b2037bed672da55104229ecc32da5abde44c26bcad01479edcfa044d09ed", "archive_sha256": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41"}, {"url": "https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.bz2", "path": "src/backend/executor/nodeSetOp.c", "label": "src/backend/executor/nodeSetOp.c", "sha256": "11d3630196d35576ca9f9a50a61946b82338de3e8871147f6cf2cb0456e70d14", "archive_sha256": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41"}, {"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": "7a94ed1652f0d74d50c39971d1cd3e8051dbc0d6058f31b6de71a433ca343521", "archive_sha256": "4d3346909b201ac1648232cf290462a7070c119326f56196f1f0253ed80fae41"}], "node_tag": "T_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u4e3a\u5217\u96c6\u5408\u5b8c\u5168\u76f8\u540c\u7684\u4e24\u4e2a\u5173\u7cfb\uff08\u5916\u4fa7\u548c\u5185\u4fa7\uff09\u3002EXCEPT \u67e5\u8be2\u4e2d\uff0c\u5916\u4fa7\u59cb\u7ec8\u662f\u5de6\u4fa7\u5173\u7cfb\uff1bINTERSECT \u4e2d\uff0c\u89c4\u5212\u5668\u5c3d\u91cf\u628a\u8f83\u5c0f\u7684\u8f93\u5165\u653e\u5728\u5916\u4fa7\u3002", "\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u5404\u8f93\u5165\u90fd\u5df2\u6309\u5168\u90e8\u5206\u7ec4\u5217\u6392\u5e8f\u3002SetOp \u8282\u70b9\u672c\u8d28\u4e0a\u6309\u5206\u7ec4\u5217\u6267\u884c\u5f52\u5e76\u8fde\u63a5\uff0c\u4f46\u53ea\u5173\u5fc3\u5404\u8f93\u5165\u6709\u591a\u5c11\u5143\u7ec4\u5339\u914d\u3002\u968f\u540e\u4fbf\u53ef\u6839\u636e SQL \u89c4\u8303\uff0c\u4e3a INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8f93\u51fa\u76f8\u5e94\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\u3002\u5148\u8bfb\u53d6\u5916\u4fa7\u5173\u7cfb\uff0c\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u7edf\u8ba1\u7ec4\u5185\u5143\u7ec4\u6570\u91cf\uff1b\u518d\u8bfb\u53d6\u5185\u4fa7\u5173\u7cfb\uff0c\u7edf\u8ba1\u4e0e\u6bcf\u4e2a\u5916\u4fa7\u5206\u7ec4\u5339\u914d\u7684\u5143\u7ec4\u6570\u91cf\u3002\uff08\u4ec5\u51fa\u73b0\u5728\u5185\u4fa7\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u53ef\u4ee5\u5ffd\u7565\u3002\uff09\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u7edf\u8ba1\u5339\u914d\u5143\u7ec4\u6570\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/summary": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/category": "Combination", "/versions/20/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/20/facts/3/label": "Output", "/versions/20/facts/3/value": "Set-operation result tuples", "/versions/20/facts/4/label": "Executor initializer", "/versions/20/facts/5/label": "Memory mechanism", "/versions/20/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/20/sections/3/paragraphs/1": "The input of a SetOp node consists of two relations (outer and inner) with identical column sets. In EXCEPT queries the outer relation is always the left side, while in INTERSECT cases the planner tries to make the outer relation be the smaller of the two inputs.", "/versions/20/sections/3/paragraphs/2": "In SETOP_SORTED mode, each input has been sorted according to all the grouping columns. The SetOp node essentially performs a merge join on the grouping columns, except that it is only interested in counting how many tuples from each input match. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/20/sections/3/paragraphs/3": "In SETOP_HASHED mode, the inputs are delivered in no particular order. We read the outer relation and build a hash table in memory with one entry for each group of identical tuples, counting the number of tuples in the group. Then we read the inner relation and count the number of tuples matching each outer group. (We can disregard any tuples appearing only in the inner relation, since they cannot result in any output.) After seeing all the input, we scan the hashtable and generate the correct output using those counts.", "/versions/20/sections/3/paragraphs/4": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need to count the number of matching tuples).", "/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": "f18fa5898e3bea437ee38fddadade09862a3e76b10bf0dc8ebaa6465b3ff4cc7"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": 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"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "node_tag": "T_SetOp", "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\uff1aSetOp, HashSetOp.", "\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": ["nodeSetOp.c\uff1a\u5904\u7406 INTERSECT \u548c EXCEPT \u9009\u62e9\u7684\u4f8b\u7a0b\u3002", "SetOp \u7684\u8f93\u5165\u4e3a\u5217\u96c6\u5408\u5b8c\u5168\u76f8\u540c\u7684\u4e24\u4e2a\u5173\u7cfb\uff08\u5916\u4fa7\u548c\u5185\u4fa7\uff09\u3002EXCEPT \u67e5\u8be2\u4e2d\uff0c\u5916\u4fa7\u59cb\u7ec8\u662f\u5de6\u4fa7\u5173\u7cfb\uff1bINTERSECT \u4e2d\uff0c\u89c4\u5212\u5668\u5c3d\u91cf\u628a\u8f83\u5c0f\u7684\u8f93\u5165\u653e\u5728\u5916\u4fa7\u3002", "\u5728 SETOP_SORTED \u6a21\u5f0f\u4e0b\uff0c\u5404\u8f93\u5165\u90fd\u5df2\u6309\u5168\u90e8\u5206\u7ec4\u5217\u6392\u5e8f\u3002SetOp \u8282\u70b9\u672c\u8d28\u4e0a\u6309\u5206\u7ec4\u5217\u6267\u884c\u5f52\u5e76\u8fde\u63a5\uff0c\u4f46\u53ea\u5173\u5fc3\u5404\u8f93\u5165\u6709\u591a\u5c11\u5143\u7ec4\u5339\u914d\u3002\u968f\u540e\u4fbf\u53ef\u6839\u636e SQL \u89c4\u8303\uff0c\u4e3a INTERSECT\u3001INTERSECT ALL\u3001EXCEPT \u6216 EXCEPT ALL \u8f93\u51fa\u76f8\u5e94\u7ed3\u679c\u3002", "\u5728 SETOP_HASHED \u6a21\u5f0f\u4e0b\uff0c\u8f93\u5165\u6ca1\u6709\u7279\u5b9a\u987a\u5e8f\u3002\u5148\u8bfb\u53d6\u5916\u4fa7\u5173\u7cfb\uff0c\u5728\u5185\u5b58\u4e2d\u6784\u5efa\u54c8\u5e0c\u8868\uff0c\u4e3a\u6bcf\u7ec4\u76f8\u540c\u5143\u7ec4\u4fdd\u7559\u4e00\u4e2a\u6761\u76ee\uff0c\u5e76\u7edf\u8ba1\u7ec4\u5185\u5143\u7ec4\u6570\u91cf\uff1b\u518d\u8bfb\u53d6\u5185\u4fa7\u5173\u7cfb\uff0c\u7edf\u8ba1\u4e0e\u6bcf\u4e2a\u5916\u4fa7\u5206\u7ec4\u5339\u914d\u7684\u5143\u7ec4\u6570\u91cf\u3002\uff08\u4ec5\u51fa\u73b0\u5728\u5185\u4fa7\u5173\u7cfb\u4e2d\u7684\u5143\u7ec4\u4e0d\u53ef\u80fd\u4ea7\u751f\u8f93\u51fa\uff0c\u56e0\u6b64\u53ef\u4ee5\u5ffd\u7565\u3002\uff09\u8bfb\u53d6\u5168\u90e8\u8f93\u5165\u540e\uff0c\u626b\u63cf\u54c8\u5e0c\u8868\uff0c\u5229\u7528\u8ba1\u6570\u751f\u6210\u6b63\u786e\u8f93\u51fa\u3002", "\u6b64\u8282\u70b9\u4e0d\u7528\u4e8e UNION \u6216 UNION ALL\uff0c\u56e0\u4e3a\u5b83\u4eec\u6709\u66f4\u4f4e\u6210\u672c\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u65e0\u9700\u7edf\u8ba1\u5339\u914d\u5143\u7ec4\u6570\u3002"]}, {"code": "case T_SetOp:\n\t\t\tsname = \"SetOp\";\n\t\t\tswitch (((SetOp *) plan)->strategy)\n\t\t\t{\n\t\t\t\tcase SETOP_SORTED:\n\t\t\t\t\tpname = \"SetOp\";\n\t\t\t\t\tstrategy = \"Sorted\";\n\t\t\t\t\tbreak;\n\t\t\t\tcase SETOP_HASHED:\n\t\t\t\t\tpname = \"HashSetOp\";\n\t\t\t\t\tstrategy = \"Hashed\";\n\t\t\t\t\tbreak;\n\t\t\t\tdefault:\n\t\t\t\t\tpname = \"SetOp ???\";\n\t\t\t\t\tstrategy = \"???\";\n\t\t\t\t\tbreak;\n\t\t\t}\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": ["Sorted", "Hashed"], "description": ["\u4f7f\u7528\u6392\u5e8f\u6216\u54c8\u5e0c\u7b56\u7565\u6267\u884c\u6240\u9009 INTERSECT \u6216 EXCEPT \u64cd\u4f5c\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Implements the selected INTERSECT or EXCEPT operation using a sorted or hashed strategy.", "/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": "Set-operation input plans", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Set-operation result tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/facts/6/label": "EXPLAIN strategies", "/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: SetOp, HashSetOp.", "/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": "nodeSetOp.c Routines to handle INTERSECT and EXCEPT selection", "/versions/18/sections/3/paragraphs/1": "The input of a SetOp node consists of two relations (outer and inner) with identical column sets. In EXCEPT queries the outer relation is always the left side, while in INTERSECT cases the planner tries to make the outer relation be the smaller of the two inputs.", "/versions/18/sections/3/paragraphs/2": "In SETOP_SORTED mode, each input has been sorted according to all the grouping columns. The SetOp node essentially performs a merge join on the grouping columns, except that it is only interested in counting how many tuples from each input match. Then it is a simple matter to emit the output demanded by the SQL spec for INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL.", "/versions/18/sections/3/paragraphs/3": "In SETOP_HASHED mode, the inputs are delivered in no particular order. We read the outer relation and build a hash table in memory with one entry for each group of identical tuples, counting the number of tuples in the group. Then we read the inner relation and count the number of tuples matching each outer group. (We can disregard any tuples appearing only in the inner relation, since they cannot result in any output.) After seeing all the input, we scan the hashtable and generate the correct output using those counts.", "/versions/18/sections/3/paragraphs/4": "This node type is not used for UNION or UNION ALL, since those can be implemented more cheaply (there's no need to count the number of matching tuples).", "/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": "5dd747fc04583ea4741bd028a3f97ba26271be497748f8877b6e7314162148b1"}, "evidence_kind": "source and documentation", "explain_names": ["SetOp", "HashSetOp"], "partial_modes": [], "comparison_data": {"node_tag": "T_SetOp", "strategies": ["Sorted", "Hashed"], "text_names": ["SetOp", "HashSetOp"], "initializer": "ExecInitSetOp", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "80b6baf9b8a135550547930365345dffe7364bc6d31bc97675ace66822910a63", "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/nodeSetOp.c"}, "parallel_callbacks": []}, "comparison": {"left": "17", "right": "18", "status": "unchanged", "diff": ""}}