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["\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", 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"/versions/10/facts/3/value": "Merged ordered tuples", "/versions/10/facts/4/label": "Executor initializer", "/versions/10/facts/5/label": "Memory mechanism", "/versions/10/tables/0/title": "EXPLAIN labels in this source build", "/versions/10/related/1/label": "Using EXPLAIN", "/versions/10/related/2/label": "Parallel plans", "/versions/10/sections/0/title": "EXPLAIN names and attributes", "/versions/10/sections/1/title": "Memory and temporary storage", "/versions/10/sections/2/title": "Parallel execution and instrumentation", "/versions/10/sections/3/title": "Executor implementation notes", "/versions/10/sections/4/title": "EXPLAIN identity in core source", "/versions/10/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/10/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/10/sections/0/paragraphs/1": "Text names recorded by this source: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/10/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/10/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/10/sections/3/paragraphs/4": "Lock the non-leaf tables in the partition tree controlled by this node. It's a no-op for non-partitioned parent tables.", "/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": "e432c908868b21c7b68d3b6c367028e47a65458aefca7c2298793fa0ea76d335"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeMergeAppend.c"}, "parallel_callbacks": 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"src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "5652561165708e009f4c29fc5a12214794936d8d08a75e915ded8b9a9e3a973b", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}, {"url": "https://ftp.postgresql.org/pub/source/v11.22/postgresql-11.22.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "5e0511194183800e8d6eb293fd4b40639c7d3118e2d199c8e7865ba4fa4cf67f", "archive_sha256": "2cb7c97d7a0d7278851bbc9c61f467b69c094c72b81740b751108e7892ebe1f0"}], "node_tag": "T_MergeAppend", "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\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u9501\u5b9a\u6b64\u8282\u70b9\u6240\u63a7\u5236\u5206\u533a\u6811\u4e2d\u7684\u975e\u53f6\u8868\u3002\u5bf9\u4e8e\u975e\u5206\u533a\u7236\u8868\uff0c\u6b64\u64cd\u4f5c\u4e0d\u6267\u884c\u4efb\u4f55\u5de5\u4f5c\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/11/description/0": "Merges sorted child streams while preserving the required ordering.", "/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": "Multiple sorted child plans", "/versions/11/facts/3/label": "Output", "/versions/11/facts/3/value": "Merged ordered 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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/11/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/11/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/11/sections/3/paragraphs/4": "Lock the non-leaf tables in the partition tree controlled by this node. It's a no-op for non-partitioned parent tables.", "/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": "edde4067a971dc24d2b45b3ba7806a286902945382aa6865b423f80d05918bfb"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": "src/backend/commands/explain.c", "executor": "src/backend/executor/execProcnode.c", "implementation": "src/backend/executor/nodeMergeAppend.c"}, "parallel_callbacks": []}, "12": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_MergeAppend"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Merge Append"}, {"label": "\u8f93\u5165", "value": "\u591a\u4e2a\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u6309\u987a\u5e8f\u5f52\u5e76\u7684\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitMergeAppend"}, {"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/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "6ac00a11383e3122254f4911617f0975954c4171cba11eddb060300bf194e83c", "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": "Merge Append", "identity": "Merge Append"}], "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": 1105, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1105", "sha256": "d02ea84fdaa201de5d9360645a9f24bfbd2c31f7d45a639e09560ac0e6b6471d", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "line": 184, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:184", "sha256": "311b17379fe54e3f342fe5ad41c43afbdfa1b844978db2bb2eb22b82520d3256", "archive_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, {"url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "6ac00a11383e3122254f4911617f0975954c4171cba11eddb060300bf194e83c", "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_MergeAppend", "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\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/12/description/0": "Merges sorted child streams while preserving the required ordering.", "/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": "Multiple sorted child plans", "/versions/12/facts/3/label": "Output", "/versions/12/facts/3/value": "Merged ordered 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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/12/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/12/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/12/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/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": "5e5822614b82e810c9ce829364965fb1575f3d35aa2668a65b9bc4aeb0ffc8fb"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "explain_prefixes": ["Parallel"], "runtime_verified": false, "source_inventory": {"explain": 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Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": 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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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/13/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/13/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. 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"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": 1199, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1199", "sha256": "e091be4e2a083b8dea39ccd09beedede22c1716ef974da66c214a44f48be8c41", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "line": 186, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:186", "sha256": "72da1c5ad457f1d92a39ab73531701794df858419e3b89d6e6cb7079634e68fa", "archive_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, {"url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "08bc25d5f711cda3183e20c5c298ef0c1d54adea57f097317b91b3ed785028be", "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_MergeAppend", "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\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/14/description/0": "Merges sorted child streams while preserving the required ordering.", "/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": "Multiple sorted child plans", "/versions/14/facts/3/label": "Output", "/versions/14/facts/3/value": "Merged ordered 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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/14/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/14/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/14/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/versions/14/tables/0/columns/0/label": "Text-format label", "/versions/14/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "8ae76c8ae92041a29cad5fa8a50739722cba2581e795a5d43add2f7b73354d17"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "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/nodeMergeAppend.c"}, "parallel_callbacks": []}, "15": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_MergeAppend"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Merge Append"}, {"label": "\u8f93\u5165", "value": "\u591a\u4e2a\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u6309\u987a\u5e8f\u5f52\u5e76\u7684\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitMergeAppend"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "147144be4b0d1643a661b8f72dbe446587a353622ffac60b48d69568bfdef0d3", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}], "mechanism": "unclassified", "description": "\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Merge Append", "identity": "Merge Append"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=15", "label": "EXPLAIN"}, {"url": "/docs/15/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/15/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 15.19 source archive", "label": "15.19", "major": "15", "channel": "stable", "revision": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89", "source_url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "line": 1202, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1202", "sha256": "bb3b442d0f1b098aa8707335250102f027a596cd94117308bd16d1d36b258f5c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "line": 186, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:186", "sha256": "19836c50a272741a4eac653541e655437c2e00710a541e5348d6a277d0669d7c", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "147144be4b0d1643a661b8f72dbe446587a353622ffac60b48d69568bfdef0d3", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "fb4a4c8165495299131173680bc02a950d88e1ff610231fd97997bc0c9afc1d7", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}], "node_tag": "T_MergeAppend", "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\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/15/description/0": "Merges sorted child streams while preserving the required ordering.", "/versions/15/facts/0/label": "Core node tag", "/versions/15/facts/1/label": "Structured EXPLAIN Node Type", "/versions/15/facts/2/label": "Inputs", "/versions/15/facts/2/value": "Multiple sorted child plans", "/versions/15/facts/3/label": "Output", "/versions/15/facts/3/value": "Merged ordered tuples", "/versions/15/facts/4/label": "Executor initializer", "/versions/15/facts/5/label": "Memory mechanism", "/versions/15/tables/0/title": "EXPLAIN labels in this source build", "/versions/15/related/1/label": "Using EXPLAIN", "/versions/15/related/2/label": "Parallel plans", "/versions/15/sections/0/title": "EXPLAIN names and attributes", "/versions/15/sections/1/title": "Memory and temporary storage", "/versions/15/sections/2/title": "Parallel execution and instrumentation", "/versions/15/sections/3/title": "Executor implementation notes", "/versions/15/sections/4/title": "EXPLAIN identity in core source", "/versions/15/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/15/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/15/sections/0/paragraphs/1": "Text names recorded by this source: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/15/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/15/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/15/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/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": "ffc55827573cd662ee76f59ca8bc50498d72eec027cf3f430ed8a5a531efacb8"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "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/nodeMergeAppend.c"}, "parallel_callbacks": []}, "16": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_MergeAppend"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Merge Append"}, {"label": "\u8f93\u5165", "value": "\u591a\u4e2a\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u6309\u987a\u5e8f\u5f52\u5e76\u7684\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitMergeAppend"}, {"label": "\u5185\u5b58\u673a\u5236", "value": "unclassified"}], "memory": {"evidence": [{"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "7761dbab26ed532aba2767892aad0b50e422f3001ea5f37935baf9510c449e1d", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}], "mechanism": "unclassified", "description": "\u672c\u6b21\u62bd\u53d6\u4e0d\u4e3a\u6b64\u8282\u70b9\u8bbe\u5b9a\u7edf\u4e00\u7684\u5185\u5b58\u4e0a\u9650\u6216\u843d\u76d8\u7b56\u7565\u3002\u8bf7\u67e5\u770b\u540c\u4e00\u6784\u5efa\u7684\u5b9e\u73b0\u3001\u76f8\u5173\u8868\u8fbe\u5f0f\u6216\u63d0\u4f9b\u65b9\u3002", "source_notes": []}, "tables": [{"key": "explain-labels", "rows": [{"label": "Merge Append", "identity": "Merge Append"}], "title": "\u672c\u6784\u5efa\u4e2d\u7684 EXPLAIN \u6807\u7b7e", "columns": [{"key": "label", "label": "\u6587\u672c\u683c\u5f0f\u6807\u7b7e"}, {"key": "identity", "label": "\u7ed3\u6784\u5316\u8282\u70b9\u6807\u8bc6"}]}], "related": [{"url": "/wiki/sql/explain/?v=16", "label": "EXPLAIN"}, {"url": "/docs/16/using-explain.html", "label": "\u4f7f\u7528 EXPLAIN"}, {"url": "/docs/16/parallel-plans.html", "label": "\u5e76\u884c\u8ba1\u5212"}], "release": {"ref": "PostgreSQL 16.15 source archive", "label": "16.15", "major": "16", "channel": "stable", "revision": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed", "source_url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "source_snapshot_utc": ""}, "sources": [{"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "line": 1235, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1235", "sha256": "8e017f0116dbea471339b40c37a667cc9f95039e7e0329c783e5e8ce194de7e1", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "line": 186, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:186", "sha256": "e48c08e555f8cb4e4bb43df516c4b8906ce9bc374b2a745d98a1fc8c22cc5099", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "7761dbab26ed532aba2767892aad0b50e422f3001ea5f37935baf9510c449e1d", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "path": "src/include/nodes/plannodes.h", "label": "src/include/nodes/plannodes.h", "sha256": "97db47353db76326b874589a5ad0a04501cc74cd72e237e7bd956e7472c41f1f", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}], "node_tag": "T_MergeAppend", "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\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/16/description/0": "Merges sorted child streams while preserving the required ordering.", "/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": "Multiple sorted child plans", "/versions/16/facts/3/label": "Output", "/versions/16/facts/3/value": "Merged ordered 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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/16/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/16/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/16/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/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": "04c800c1b4d490c764ac0779f946f4e7fad3aca68e519add6666a59a2260f8ce"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": 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["\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": 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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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/17/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/17/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/17/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/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": "62f9d60f17913eb9f032615bb1c567bd51e29196c05049e502eeea9f22f64778"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": 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Type\u3002\u6587\u672c\u683c\u5f0f\u540d\u79f0\u8fd8\u53ef\u80fd\u5305\u542b\u64cd\u4f5c\u3001\u7b56\u7565\u3001\u8fde\u63a5\u7c7b\u578b\u3001\u626b\u63cf\u65b9\u5411\u6216\u805a\u5408\u9636\u6bb5\u5c5e\u6027\u3002", "\u6b64\u6e90\u7801\u8bb0\u5f55\u7684\u6587\u672c\u540d\u79f0\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Merges sorted child streams while preserving the required ordering.", "/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": "Multiple sorted child plans", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Merged ordered 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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/18/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/18/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/18/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/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": "39dd443790be051c1f08ec4b41208630f8598aebd51eed34cba93db02b558c9d"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "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/nodeMergeAppend.c"}, "parallel_callbacks": []}, "19": {"facts": [{"label": "\u6838\u5fc3\u8282\u70b9\u6807\u7b7e", "value": "T_MergeAppend"}, {"label": "\u7ed3\u6784\u5316 EXPLAIN \u8282\u70b9\u7c7b\u578b", "value": "Merge Append"}, {"label": "\u8f93\u5165", "value": "\u591a\u4e2a\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212"}, {"label": "\u8f93\u51fa", "value": "\u6309\u987a\u5e8f\u5f52\u5e76\u7684\u5143\u7ec4"}, {"label": "\u6267\u884c\u5668\u521d\u59cb\u5316\u51fd\u6570", "value": "ExecInitMergeAppend"}, {"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/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "cd6b75beb7b83bf268593aa6462afbd211fd9b711ba3d0afb3e8ecb12048c90e", "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": "Merge Append", "identity": "Merge Append"}], "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": 1421, "path": "src/backend/commands/explain.c", "label": "src/backend/commands/explain.c:1421", "sha256": "8b115b1c194a4b54ae630209a741e293b1df49a9052f10b2de9ca092a48998e3", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, {"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "line": 186, "path": "src/backend/executor/execProcnode.c", "label": "src/backend/executor/execProcnode.c:186", "sha256": "5e39b2037bed672da55104229ecc32da5abde44c26bcad01479edcfa044d09ed", "archive_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, {"url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "cd6b75beb7b83bf268593aa6462afbd211fd9b711ba3d0afb3e8ecb12048c90e", "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_MergeAppend", "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\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/19/description/0": "Merges sorted child streams while preserving the required ordering.", "/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": "Multiple sorted child plans", "/versions/19/facts/3/label": "Output", "/versions/19/facts/3/value": "Merged ordered 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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/19/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/19/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/19/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/versions/19/tables/0/columns/0/label": "Text-format label", "/versions/19/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "d9bbc9198e4f09945a84f0219b8a1eb9841a67012ab72ce5c7a7f28db375128d"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": 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["\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": 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plans", "/versions/20/sections/0/title": "EXPLAIN names and attributes", "/versions/20/sections/1/title": "Memory and temporary storage", "/versions/20/sections/2/title": "Parallel execution and instrumentation", "/versions/20/sections/3/title": "Executor implementation notes", "/versions/20/sections/4/title": "EXPLAIN identity in core source", "/versions/20/memory/description": "This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.", "/versions/20/sections/0/paragraphs/0": "Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.", "/versions/20/sections/0/paragraphs/1": "Text names recorded by this source: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/20/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/20/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/20/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/versions/20/tables/0/columns/0/label": "Text-format label", "/versions/20/tables/0/columns/1/label": "Structured node identity"}, "fallback_fields": [], "source_language": "en", "original_snapshot_sha256": "deb1217eb806d8baebde9041aefcc6f9276214f03331dd5ebecb1a192b6cfc11"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "explain_prefixes": ["Parallel", "Async"], "runtime_verified": false, "source_inventory": {"explain": 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{"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "path": "src/backend/executor/nodeMergeAppend.c", "label": "src/backend/executor/nodeMergeAppend.c", "sha256": "1b2b532b2b964d9312554f28334c603928340a89599d23860209acf9105a06df", "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_MergeAppend", "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\uff1aMerge Append.", "\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": ["\u8bf4\u660e\uff1aMergeAppend \u5305\u542b\u4e00\u4e2a\u6216\u591a\u4e2a\u5b50\u8ba1\u5212\uff0c\u8981\u6c42\u5b83\u4eec\u6309\u540c\u4e00\u6392\u5e8f\u952e\u8f93\u51fa\u5143\u7ec4\u3002\u8be5\u8282\u70b9\u5f52\u5e76\u8fd9\u4e9b\u6d41\uff0c\u4ea7\u751f\u6309\u76f8\u540c\u987a\u5e8f\u6392\u5217\u7684\u8f93\u51fa\u3002", "MergeAppend \u8282\u70b9\u4e0d\u4f7f\u7528\u5de6\u53f3\u5b50\u6811\uff0c\u800c\u662f\u7ef4\u62a4\u4e00\u4e2a\u5b50\u8ba1\u5212\u5217\u8868\uff0c\u56e0\u6b64\u5178\u578b\u8282\u70b9\u5728\u8ba1\u5212\u6811\u4e2d\u7684\u5f62\u6001\u5982\u4e0b\uff1a", "... / MergeAppend---+------+------+--- nil / \\ | | | nil nil ... ... ... subplans", "\u5806\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u5bf9\u5e94\u4e00\u4e2a\u69fd\u4f4d\uff0c\u4f7f\u7528 SlotNumber \u5b58\u50a8\u69fd\u4f4d\u7d22\u5f15\u3002\u8fd9\u5e76\u4e0d\u771f\u6b63\u63d0\u4f9b\u7c7b\u578b\u5b89\u5168\uff0c\u4f46\u80fd\u4f7f\u4ee3\u7801\u542b\u4e49\u66f4\u6e05\u695a\u3002", "\u82e5\u5df2\u542f\u7528\u8fd0\u884c\u65f6\u5206\u533a\u88c1\u526a\uff0c\u5219\u73b0\u5728\u8fdb\u884c\u76f8\u5e94\u8bbe\u7f6e\u3002"]}, {"code": "case T_MergeAppend:\n\t\t\tpname = sname = \"Merge Append\";\n\t\t\tbreak;", "title": "\u6838\u5fc3\u6e90\u7801\u4e2d\u7684 EXPLAIN \u6807\u8bc6"}], "strategies": [], "description": ["\u5f52\u5e76\u5df2\u6392\u5e8f\u7684\u5b50\u8ba1\u5212\u6d41\uff0c\u5e76\u4fdd\u6301\u8981\u6c42\u7684\u987a\u5e8f\u3002"], "localization": {"status": "complete", "sources": [], "language": "zh", "original_text": {"/versions/18/description/0": "Merges sorted child streams while preserving the required ordering.", "/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": "Multiple sorted child plans", "/versions/18/facts/3/label": "Output", "/versions/18/facts/3/value": "Merged ordered 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: Merge Append.", "/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": "NOTES A MergeAppend node contains a list of one or more subplans. These are each expected to deliver tuples that are sorted according to a common sort key. The MergeAppend node merges these streams to produce output sorted the same way.", "/versions/18/sections/3/paragraphs/1": "MergeAppend nodes don't make use of their left and right subtrees, rather they maintain a list of subplans so a typical MergeAppend node looks like this in the plan tree:", "/versions/18/sections/3/paragraphs/3": "We have one slot for each item in the heap array. We use SlotNumber to store slot indexes. This doesn't actually provide any formal type-safety, but it makes the code more self-documenting.", "/versions/18/sections/3/paragraphs/4": "If run-time partition pruning is enabled, then set that up now", "/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": "39dd443790be051c1f08ec4b41208630f8598aebd51eed34cba93db02b558c9d"}, "evidence_kind": "source and documentation", "explain_names": ["Merge Append"], "partial_modes": [], "comparison_data": {"node_tag": "T_MergeAppend", "strategies": [], "text_names": ["Merge Append"], "initializer": "ExecInitMergeAppend", "partial_modes": [], "memory_mechanism": "unclassified", "parallel_callbacks": []}, "comparison_hash": "5428ffe21c76597da696d12a775fd915b1be22e9ba2d2d5ba3d84704f51ff3d9", "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/nodeMergeAppend.c"}, "parallel_callbacks": []}, "comparison": {"left": "17", "right": "18", "status": "unchanged", "diff": ""}}