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["\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\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": 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"\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/10/description/0": "Evaluates and scans a VALUES row list.", "/versions/10/facts/0/label": "Core node tag", "/versions/10/facts/1/label": "Structured EXPLAIN Node Type", "/versions/10/facts/2/label": "Inputs", "/versions/10/facts/2/value": "A list of row expressions", "/versions/10/facts/3/label": "Output", "/versions/10/facts/3/value": "VALUES tuples", "/versions/10/facts/4/label": "Executor initializer", "/versions/10/facts/5/label": "Memory mechanism", "/versions/10/tables/0/title": "EXPLAIN labels in this source build", "/versions/10/related/1/label": "Using EXPLAIN", "/versions/10/related/2/label": "Parallel plans", "/versions/10/sections/0/title": "EXPLAIN names and attributes", "/versions/10/sections/1/title": "Memory and temporary storage", "/versions/10/sections/2/title": 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Inspect the same-build implementation and its expressions or provider.", "/versions/10/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/10/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/10/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/10/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/10/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/10/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/10/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/10/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/10/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/10/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/10/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "71223520081277448247c6fa3a9afc8c7d664d348e05dcbd0110c6c5ba21159e"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": 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"\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/11/description/0": "Evaluates and scans a VALUES row list.", "/versions/11/facts/0/label": "Core node tag", "/versions/11/facts/1/label": "Structured EXPLAIN Node Type", "/versions/11/facts/2/label": "Inputs", "/versions/11/facts/2/value": "A list of row expressions", "/versions/11/facts/3/label": "Output", "/versions/11/facts/3/value": "VALUES tuples", "/versions/11/facts/4/label": "Executor initializer", "/versions/11/facts/5/label": "Memory mechanism", "/versions/11/tables/0/title": "EXPLAIN labels in this source build", "/versions/11/related/1/label": "Using EXPLAIN", "/versions/11/related/2/label": "Parallel plans", "/versions/11/sections/0/title": "EXPLAIN names and attributes", "/versions/11/sections/1/title": "Memory and temporary storage", "/versions/11/sections/2/title": "Parallel execution and instrumentation", "/versions/11/sections/3/title": "Executor implementation notes", "/versions/11/sections/4/title": "EXPLAIN identity in core source", "/versions/11/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/11/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/11/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/11/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/11/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/11/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/11/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/11/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/11/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/11/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/11/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/11/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "bbb89f5cf10732dd2d3271b53bdc8dbbea12cc06af495540e40e5a02965e4620"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeValuesscan.c"}, "parallel_callbacks": []}, "12": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_ValuesScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Values Scan"}, {"label": "\u8f93\u5165", "value": "\u884c\u8868\u8fbe\u5f0f\u5217\u8868"}, {"label": "\u8f93\u51fa", "value": "VALUES \u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitValuesScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "84946888a5f5c489ef629e811c51a5acbe7cb7a2fd9e15505ac52f95d531ae4b", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}], "mechanism": "unclassified", "description": "\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Values Scan", "identity": "Values Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=12", "label": "EXPLAIN"}, {"url": "/docs/12/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/12/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 12.22 source archive", "label": "12.22", "major": "12", "channel": "historical", "revision": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b", "source_url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "line": 1164, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1164", "sha256": "d02ea84fdaa201de5d9360645a9f24bfbd2c31f7d45a639e09560ac0e6b6471d", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "line": 257, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:257", "sha256": "311b17379fe54e3f342fe5ad41c43afbdfa1b844978db2bb2eb22b82520d3256", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "84946888a5f5c489ef629e811c51a5acbe7cb7a2fd9e15505ac52f95d531ae4b", "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_ValuesScan", "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\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/12/description/0": "Evaluates and scans a VALUES row list.", "/versions/12/facts/0/label": "Core node tag", "/versions/12/facts/1/label": "Structured EXPLAIN Node Type", "/versions/12/facts/2/label": "Inputs", "/versions/12/facts/2/value": "A list of row expressions", "/versions/12/facts/3/label": "Output", "/versions/12/facts/3/value": "VALUES tuples", "/versions/12/facts/4/label": "Executor initializer", "/versions/12/facts/5/label": "Memory mechanism", "/versions/12/tables/0/title": "EXPLAIN labels in this source build", "/versions/12/related/1/label": "Using EXPLAIN", "/versions/12/related/2/label": "Parallel plans", "/versions/12/sections/0/title": "EXPLAIN names and attributes", "/versions/12/sections/1/title": "Memory and temporary storage", "/versions/12/sections/2/title": "Parallel execution and instrumentation", "/versions/12/sections/3/title": "Executor implementation notes", "/versions/12/sections/4/title": "EXPLAIN identity in core source", "/versions/12/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/12/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/12/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/12/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/12/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/12/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/12/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/12/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/12/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/12/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/12/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/12/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "a3999a26b856f30b6638e4a18a186bcd53f74e8f74470ccf124665189e423625"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeValuesscan.c"}, "parallel_callbacks": []}, "13": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_ValuesScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Values Scan"}, {"label": "\u8f93\u5165", "value": "\u884c\u8868\u8fbe\u5f0f\u5217\u8868"}, {"label": "\u8f93\u51fa", "value": "VALUES \u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitValuesScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "09ac956ba10806460f12d6222cd5da6f1520ccfc3eb128894aaef19baecb7922", "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": "Values Scan", "identity": "Values Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=13", "label": "EXPLAIN"}, {"url": "/docs/13/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/13/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 13.23 source archive", "label": "13.23", "major": "13", "channel": "historical", "revision": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6", "source_url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "line": 1222, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1222", "sha256": "541713e0e7f1c9cc352c2b6028964d440c19d2678a4463000094c24a88c1e730", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "line": 257, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:257", "sha256": "d085ee99acfa00587e6ade3a1d9f8108a0566beedbbee3f54a50c9fc0cc2e875", "archive_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, {"url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "09ac956ba10806460f12d6222cd5da6f1520ccfc3eb128894aaef19baecb7922", "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_ValuesScan", "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\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/13/description/0": "Evaluates and scans a VALUES row list.", "/versions/13/facts/0/label": "Core node tag", "/versions/13/facts/1/label": "Structured EXPLAIN Node Type", "/versions/13/facts/2/label": "Inputs", "/versions/13/facts/2/value": "A list of row expressions", "/versions/13/facts/3/label": "Output", "/versions/13/facts/3/value": "VALUES tuples", "/versions/13/facts/4/label": "Executor initializer", "/versions/13/facts/5/label": "Memory mechanism", "/versions/13/tables/0/title": "EXPLAIN labels in this source build", "/versions/13/related/1/label": "Using EXPLAIN", "/versions/13/related/2/label": "Parallel plans", "/versions/13/sections/0/title": "EXPLAIN names and attributes", "/versions/13/sections/1/title": "Memory and temporary storage", "/versions/13/sections/2/title": "Parallel execution and instrumentation", "/versions/13/sections/3/title": "Executor implementation notes", "/versions/13/sections/4/title": "EXPLAIN identity in core source", "/versions/13/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/13/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/13/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/13/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/13/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/13/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/13/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/13/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/13/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/13/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/13/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/13/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "7bee60b9e92cc3f87dfe733452e840472921aa30d9b99840d822c75cf1a045c0"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeValuesscan.c"}, "parallel_callbacks": []}, "14": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_ValuesScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Values Scan"}, {"label": "\u8f93\u5165", "value": "\u884c\u8868\u8fbe\u5f0f\u5217\u8868"}, {"label": "\u8f93\u51fa", "value": "VALUES \u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitValuesScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "7c45d41aeea1f1af0a619e1755b9f1b1428b01f08f5e24e2c72a658997cccc79", "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": "Values Scan", "identity": "Values Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=14", "label": "EXPLAIN"}, {"url": "/docs/14/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/14/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 14.24 source archive", "label": "14.24", "major": "14", "channel": "stable", "revision": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897", "source_url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "line": 1261, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1261", "sha256": "e091be4e2a083b8dea39ccd09beedede22c1716ef974da66c214a44f48be8c41", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "line": 264, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:264", "sha256": "72da1c5ad457f1d92a39ab73531701794df858419e3b89d6e6cb7079634e68fa", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "7c45d41aeea1f1af0a619e1755b9f1b1428b01f08f5e24e2c72a658997cccc79", "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_ValuesScan", "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\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/14/description/0": "Evaluates and scans a VALUES row list.", "/versions/14/facts/0/label": "Core node tag", "/versions/14/facts/1/label": "Structured EXPLAIN Node Type", "/versions/14/facts/2/label": "Inputs", "/versions/14/facts/2/value": "A list of row expressions", "/versions/14/facts/3/label": "Output", "/versions/14/facts/3/value": "VALUES tuples", "/versions/14/facts/4/label": "Executor initializer", "/versions/14/facts/5/label": "Memory mechanism", "/versions/14/tables/0/title": "EXPLAIN labels in this source build", "/versions/14/related/1/label": "Using EXPLAIN", "/versions/14/related/2/label": "Parallel plans", "/versions/14/sections/0/title": "EXPLAIN names and attributes", "/versions/14/sections/1/title": "Memory and temporary storage", "/versions/14/sections/2/title": "Parallel execution and instrumentation", "/versions/14/sections/3/title": "Executor implementation notes", "/versions/14/sections/4/title": "EXPLAIN identity in core source", "/versions/14/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/14/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/14/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/14/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/14/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/14/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/14/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/14/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/14/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/14/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/14/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/14/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. 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\u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], 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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: Values Scan.", "/versions/15/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/15/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/15/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/15/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/15/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/15/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/15/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/15/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/15/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "da592b7559e86fb62ca3796334eaa1a15183c200dab5efc70ba3237e1aea5460"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": 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"\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/16/description/0": "Evaluates and scans a VALUES row list.", "/versions/16/facts/0/label": "Core node tag", "/versions/16/facts/1/label": "Structured EXPLAIN Node Type", "/versions/16/facts/2/label": "Inputs", "/versions/16/facts/2/value": "A list of row expressions", "/versions/16/facts/3/label": "Output", "/versions/16/facts/3/value": "VALUES tuples", "/versions/16/facts/4/label": "Executor initializer", "/versions/16/facts/5/label": "Memory mechanism", "/versions/16/tables/0/title": "EXPLAIN labels in this source build", "/versions/16/related/1/label": "Using EXPLAIN", "/versions/16/related/2/label": "Parallel plans", "/versions/16/sections/0/title": "EXPLAIN names and attributes", "/versions/16/sections/1/title": "Memory and temporary storage", "/versions/16/sections/2/title": "Parallel execution and instrumentation", "/versions/16/sections/3/title": "Executor implementation notes", "/versions/16/sections/4/title": "EXPLAIN identity in core source", "/versions/16/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/16/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/16/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/16/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/16/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/16/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/16/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/16/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/16/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/16/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/16/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/16/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "bc97f19b25a4b6392abeec32f1f87d3438ad5d943e3316546d797b117d260a5d"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": 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"\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/17/description/0": "Evaluates and scans a VALUES row list.", "/versions/17/facts/0/label": "Core node tag", "/versions/17/facts/1/label": "Structured EXPLAIN Node Type", "/versions/17/facts/2/label": "Inputs", "/versions/17/facts/2/value": "A list of row expressions", "/versions/17/facts/3/label": "Output", "/versions/17/facts/3/value": "VALUES tuples", "/versions/17/facts/4/label": "Executor initializer", "/versions/17/facts/5/label": "Memory mechanism", "/versions/17/tables/0/title": "EXPLAIN labels in this source build", "/versions/17/related/1/label": "Using EXPLAIN", "/versions/17/related/2/label": "Parallel plans", "/versions/17/sections/0/title": "EXPLAIN names and attributes", "/versions/17/sections/1/title": "Memory and temporary storage", "/versions/17/sections/2/title": "Parallel execution and instrumentation", "/versions/17/sections/3/title": "Executor implementation notes", "/versions/17/sections/4/title": "EXPLAIN identity in core source", "/versions/17/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/17/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/17/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/17/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/17/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/17/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/17/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/17/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/17/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/17/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/17/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/17/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "9e9ce15d3cd4e804819528dfa11f3c08827b356b8b87bebdf0410937bd85e2d6"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "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/nodeValuesscan.c"}, "parallel_callbacks": []}, "18": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_ValuesScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Values Scan"}, {"label": "\u8f93\u5165", "value": "\u884c\u8868\u8fbe\u5f0f\u5217\u8868"}, {"label": "\u8f93\u51fa", "value": "VALUES \u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitValuesScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "2cbd81c45f271df78a8ff17890449ff527f2b49b29187b6d61767f321165b2a3", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}], "mechanism": "unclassified", "description": "\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Values Scan", "identity": "Values Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=18", "label": "EXPLAIN"}, {"url": "/docs/18/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/18/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 18.6 source archive", "label": "18.6", "major": "18", "channel": "stable", "revision": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f", "source_url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 1471, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1471", "sha256": "34c86d6070224a0e981efef51f79101d6d505e5874f1684ace183034bab14bb4", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "line": 264, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:264", "sha256": "f8a06a3f539077249b20664b2812433db6d7bd12b2c0ca633525db43d06f112a", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "2cbd81c45f271df78a8ff17890449ff527f2b49b29187b6d61767f321165b2a3", "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_ValuesScan", "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\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Evaluates and scans a VALUES row list.", "/versions/18/facts/0/label": "Core node tag", "/versions/18/facts/1/label": "Structured EXPLAIN Node Type", "/versions/18/facts/2/label": "Inputs", "/versions/18/facts/2/value": "A list of row expressions", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "VALUES tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/tables/0/title": "EXPLAIN labels in this source build", "/versions/18/related/1/label": "Using EXPLAIN", "/versions/18/related/2/label": "Parallel plans", "/versions/18/sections/0/title": "EXPLAIN names and attributes", "/versions/18/sections/1/title": "Memory and temporary storage", "/versions/18/sections/2/title": "Parallel execution and instrumentation", "/versions/18/sections/3/title": "Executor implementation notes", "/versions/18/sections/4/title": "EXPLAIN identity in core source", "/versions/18/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/18/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/18/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/18/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/18/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/18/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/18/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/18/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/18/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/18/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/18/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/18/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "3e49628335c6a35403d337297cd44d788ae8ee46574ba6b1b4eebb7b245f3c04"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "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/nodeValuesscan.c"}, "parallel_callbacks": []}, "19": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_ValuesScan"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Values Scan"}, {"label": "\u8f93\u5165", "value": "\u884c\u8868\u8fbe\u5f0f\u5217\u8868"}, {"label": "\u8f93\u51fa", "value": "VALUES \u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitValuesScan"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "26e7af6029ea516611896fe704f799f33885c75534b8beea89a8d28c746113bc", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}], "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": "Values Scan", "identity": "Values Scan"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=19", "label": "EXPLAIN"}, {"url": "/docs/19/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/19/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 19beta4 source archive", "label": "19beta4", "major": "19", "channel": "preview", "revision": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86", "source_url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "line": 1483, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1483", "sha256": "8b115b1c194a4b54ae630209a741e293b1df49a9052f10b2de9ca092a48998e3", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, {"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "line": 264, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:264", "sha256": "5e39b2037bed672da55104229ecc32da5abde44c26bcad01479edcfa044d09ed", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, {"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "path": "src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "26e7af6029ea516611896fe704f799f33885c75534b8beea89a8d28c746113bc", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, {"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "1c65d5d6b6c81c71531685843647869bcae630779d815a5036b06e070c6c06c7", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}], "node_tag": "T_ValuesScan", "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\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/19/description/0": "Evaluates and scans a VALUES row list.", "/versions/19/facts/0/label": "Core node tag", "/versions/19/facts/1/label": "Structured EXPLAIN Node Type", "/versions/19/facts/2/label": "Inputs", "/versions/19/facts/2/value": "A list of row expressions", "/versions/19/facts/3/label": "Output", "/versions/19/facts/3/value": "VALUES tuples", "/versions/19/facts/4/label": "Executor initializer", "/versions/19/facts/5/label": "Memory mechanism", "/versions/19/tables/0/title": "EXPLAIN labels in this source build", "/versions/19/related/1/label": "Using EXPLAIN", "/versions/19/related/2/label": "Parallel plans", "/versions/19/sections/0/title": "EXPLAIN names and attributes", "/versions/19/sections/1/title": "Memory and temporary storage", "/versions/19/sections/2/title": "Parallel execution and instrumentation", "/versions/19/sections/3/title": "Executor implementation notes", "/versions/19/sections/4/title": "EXPLAIN identity in core source", "/versions/19/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/19/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/19/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/19/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/19/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/19/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/19/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/19/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/19/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/19/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/19/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/19/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. 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\u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], 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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: Values Scan.", "/versions/20/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/20/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/20/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/20/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/20/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/20/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/20/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. 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"src/backend/executor/nodeValuesscan.c", "label": "src/backend/executor/nodeValuesscan.c", "sha256": "2cbd81c45f271df78a8ff17890449ff527f2b49b29187b6d61767f321165b2a3", "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_ValuesScan", "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\uff1aValues Scan.", "\u5e76\u884c\u611f\u77e5\u4e0e\u5e76\u884c\u5b89\u5168\u662f\u4e0d\u540c\u7684\u8ba1\u5212\u5c5e\u6027\u3002\u5728\u5e76\u884c\u5de5\u4f5c\u8fdb\u7a0b\u5185\u8fd0\u884c\u7684\u8282\u70b9\u4e0d\u4e00\u5b9a\u662f\u5e76\u884c\u611f\u77e5\u8282\u70b9\u3002"]}, {"title": "\u5185\u5b58\u4e0e\u4e34\u65f6\u5b58\u50a8", "paragraphs": ["\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002"]}, {"title": "\u5e76\u884c\u6267\u884c\u4e0e\u8fd0\u884c\u4fe1\u606f\u91c7\u96c6", "paragraphs": ["\u4ee5\u4e0b\u6e90\u7801\u56de\u8c03\u53ef\u4ee5\u534f\u8c03\u6267\u884c\u6216\u6536\u96c6\u5de5\u4f5c\u8fdb\u7a0b\u7684\u6d4b\u91cf\u6570\u636e\u3002\u56de\u8c03\u5b58\u5728\u4e0d\u4ee3\u8868\u8be5\u8282\u70b9\u666e\u904d\u652f\u6301\u5171\u4eab\u5e76\u884c\u626b\u63cf\u6216\u5171\u4eab\u72b6\u6001\u3002", "\u6b64\u6784\u5efa\u7684\u56de\u8c03\uff1anone extracted from this node implementation."]}, {"title": "\u6267\u884c\u5668\u5b9e\u73b0\u8bf4\u660e", "paragraphs": ["nodeValuesscan.c\uff1a\u652f\u6301\u626b\u63cf VALUES \u5217\u8868\uff08\u8303\u56f4\u8868\u4e2d\u7684 VALUES (...), (...), ...\uff09\u7684\u4f8b\u7a0b\u3002", "\u59cb\u7ec8\u6e05\u7a7a\u7ed3\u679c\u69fd\u3002\u5230\u8fbe\u6570\u636e\u672b\u5c3e\u65f6\u5e94\u5f53\u5982\u6b64\uff1b\u5373\u4f7f\u5c1a\u672a\u5230\u8fbe\u672b\u5c3e\uff0c\u8fd9\u4e5f\u662f\u5b58\u50a8\u865a\u62df\u5143\u7ec4\u534f\u8bae\u7684\u7b2c\u4e00\u6b65\u3002\u5982\u679c\u69fd\u53ef\u80fd\u6307\u5411\u67d0\u4e2a\u5185\u5b58\u4e0a\u4e0b\u6587\u4e2d\u7684\u6570\u636e\uff0c\u5e94\u5148\u6e05\u7a7a\u69fd\uff0c\u518d\u91cd\u7f6e\u8be5\u4e0a\u4e0b\u6587\u3002", "\u6e05\u7406\u4e0a\u4e00\u8f6e\u9057\u7559\u7684\u6570\u636e\u3002\u4f7f\u7528 ReScanExprContext \u800c\u975e\u4ec5\u4f7f\u7528 ResetExprContext\uff0c\u662f\u56e0\u4e3a\u9700\u8981\u8c03\u7528\u6240\u6709\u5df2\u6ce8\u518c\u7684\u5173\u95ed\u56de\u8c03\u3002", "\u9664\u975e\u5df2\u4e3a\u8be5\u884c\u5efa\u7acb\u8868\u8fbe\u5f0f\u6c42\u503c\u72b6\u6001\uff0c\u5426\u5219\u5728 econtext \u7684\u9010\u5143\u7ec4\u5185\u5b58\u4e2d\u521b\u5efa\u3002\u8fd9\u6709\u4e9b\u7279\u522b\uff0c\u4f46\u79fb\u5230\u4e0b\u4e00\u884c\u65f6\u9700\u8981\u518d\u6b21\u5220\u9664\u8be5\u72b6\u6001\uff0c\u9632\u6b62\u8f83\u957f VALUES \u5217\u8868\u6301\u7eed\u589e\u52a0\u5185\u5b58\u9700\u6c42\u3002\u65e0\u6cd5\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u7684\u884c\uff0c\u5df2\u5728\u8ba1\u5212\u542f\u52a8\u65f6\u5efa\u7acb\u6c42\u503c\u72b6\u6001\u3002", "parent \u4f20 NULL\uff0c\u800c\u975e\u5f53\u524d\u8ba1\u5212\u8282\u70b9\uff0c\u4ee5\u514d\u6b64\u4e34\u65f6\u72b6\u6001\u4e2d\u7684\u5185\u5bb9\u94fe\u63a5\u5230\u6c38\u4e45\u72b6\u6001\u3002\u552f\u4e00\u53ef\u80fd\u8fd9\u6837\u505a\u7684\u8868\u8fbe\u5f0f\u7c7b\u578b\u662f SubPlan\uff0c\u800c\u6b64\u524d\u5df2\u68c0\u67e5\u4e0d\u5b58\u5728\u8fd9\u79cd\u8868\u8fbe\u5f0f\u3002"]}, {"code": "case T_ValuesScan:\n\t\t\tpname = sname = \"Values Scan\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u8ba1\u7b97\u5e76\u626b\u63cf VALUES \u884c\u5217\u8868\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Evaluates and scans a VALUES row list.", "/versions/18/facts/0/label": "Core node tag", "/versions/18/facts/1/label": "Structured EXPLAIN Node Type", "/versions/18/facts/2/label": "Inputs", "/versions/18/facts/2/value": "A list of row expressions", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "VALUES tuples", "/versions/18/facts/4/label": "Executor initializer", "/versions/18/facts/5/label": "Memory mechanism", "/versions/18/tables/0/title": "EXPLAIN labels in this source build", "/versions/18/related/1/label": "Using EXPLAIN", "/versions/18/related/2/label": "Parallel plans", "/versions/18/sections/0/title": "EXPLAIN names and attributes", "/versions/18/sections/1/title": "Memory and temporary storage", "/versions/18/sections/2/title": "Parallel execution and instrumentation", "/versions/18/sections/3/title": "Executor implementation notes", "/versions/18/sections/4/title": "EXPLAIN identity in core source", "/versions/18/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/18/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/18/sections/0/paragraphs/1": "Text names recorded by this source: Values Scan.", "/versions/18/sections/0/paragraphs/2": "Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.", "/versions/18/sections/1/paragraphs/0": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/18/sections/2/paragraphs/0": "The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.", "/versions/18/sections/2/paragraphs/1": "Callbacks in this build: none extracted from this node implementation.", "/versions/18/sections/3/paragraphs/0": "nodeValuesscan.c Support routines for scanning Values lists (\"VALUES (...), (...), ...\" in rangetable).", "/versions/18/sections/3/paragraphs/1": "Always clear the result slot; this is appropriate if we are at the end of the data, and if we're not, we still need it as the first step of the store-virtual-tuple protocol. It seems wise to clear the slot before we reset the context it might have pointers into.", "/versions/18/sections/3/paragraphs/2": "Get rid of any prior cycle's leftovers. We use ReScanExprContext not just ResetExprContext because we want any registered shutdown callbacks to be called.", "/versions/18/sections/3/paragraphs/3": "Unless we already made the expression eval state for this row, build it in the econtext's per-tuple memory. This is a tad unusual, but we want to delete the eval state again when we move to the next row, to avoid growth of memory requirements over a long values list. For rows in which that won't work, we already built the eval state at plan startup.", "/versions/18/sections/3/paragraphs/4": "Pass parent as NULL, not my plan node, because we don't want anything in this transient state linking into permanent state. The only expression type that might wish to do so is a SubPlan, and we already checked that there aren't any.", "/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": "3e49628335c6a35403d337297cd44d788ae8ee46574ba6b1b4eebb7b245f3c04"}, "evidence_kind": "source and documentation", "explain_names": ["Values Scan"], "partial_modes": [], "comparison_data": {"node_tag": "T_ValuesScan", "strategies": [], "text_names": ["Values Scan"], "initializer": "ExecInitValuesScan", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "a0f7ecd83c2ff3883a8f6be3d13bd28e040a53da79545a3140489e6b4a0e75e8", "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/nodeValuesscan.c"}, "parallel_callbacks": []}, "comparison": {"left": "17", "right": "18", "status": "unchanged", "diff": ""}}