{"Entry":{"collection":"protocol","key":"logical-truncate","name":"Truncate (logical replication)","aliases":["Truncate"],"metadata":{"aliases":["Truncate"],"category":"Logical replication formats","content_hash":"f026ebf95e4a9fb0711de41ccd64e6b914eb41f4f600c7ee984bb7996d12176c","derived_content_hash":"f353f6bfdee5b59e89a81d8678fa46a1d24a04addf44871b48cfaee0f99aca38","imported_at":"2026-09-30T00:40:44.665058+08:00","name":"Truncate (logical replication)","name_zh":"","slug":"logical-truncate","summary":"Logical replication Truncate format. Identifies the message as a truncate message."}},"Definition":{"Collection":"protocol","Key":"logical-truncate","SourceDatabase":"center","Version":"18","SourceTable":"protocol_message","SourceKey":"logical-truncate","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","Facts":{"comparison_data":{"fields":[{"description":"Identifies the message as a truncate message.","format":"Byte1('T')"},{"description":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.","format":"Int32 (TransactionId)"},{"description":"Number of relations","format":"Int32"},{"description":"Option bits for TRUNCATE : 1 for CASCADE , 2 for RESTART IDENTITY","format":"Int8"},{"description":"OID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.","format":"Int32 (Oid)"}],"layer":"logical replication"},"comparison_hash":"5d3d7c086cb42d41761421f20d31df19f38aa6c7bbce4ca0a36f54c516cb31de","description":["Logical replication Truncate format. Identifies the message as a truncate message."],"description_zh":"Byte1('T') 将该消息标识为 Truncate 消息。 Int32 (TransactionId) 事务的 Xid（仅在流式传输的事务中出现）。此字段从协议版本 2 起可用。 Int32 关系数量 Int8 选项位用于 TRUNCATE 命令：1 表示 CASCADE ，2 表示 RESTART IDENTITY Int32 (Oid) 关系的 OID，与 Relation 消息中的 ID 对应。每个关系都重复出现此字段。","description_zh_html":"\u003cp\u003e协议消息 Truncate。\u003c/p\u003e\u003ch3\u003e同版本中文手册定义\u003c/h3\u003e\u003cdd\u003e\u003cdiv class=\"variablelist\"\u003e\u003cdl class=\"variablelist\"\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('T')\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         将该消息标识为 Truncate 消息。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32 (TransactionId)\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         事务的 Xid（仅在流式传输的事务中出现）。此字段从协议版本 2 起可用。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         关系数量\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt8\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         选项位用于 \u003ccode class=\"command\"\u003eTRUNCATE\u003c/code\u003e 命令：1 表示 \u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e，2 表示 \u003ccode class=\"literal\"\u003eRESTART IDENTITY\u003c/code\u003e\n\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32 (Oid)\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         关系的 OID，与 Relation 消息中的 ID 对应。每个关系都重复出现此字段。\n        \u003c/p\u003e\u003c/dd\u003e\u003c/dl\u003e\u003c/div\u003e\u003c/dd\u003e\u003cp\u003e\u003ca href=\"/zh/docs/18/protocol-logicalrep-message-formats.html#PROTOCOL-LOGICALREP-MESSAGE-FORMATS-TRUNCATE\"\u003e查看完整中文手册与上下文\u003c/a\u003e。\u003c/p\u003e","facts":[{"label":"Layer","value":"Logical replication payload; distinct from the frontend/backend message envelope"},{"label":"First field","value":"Byte1('T')"}],"facts_zh":[{"label":"层次","value":"逻辑复制载荷，与前后端消息封装分开。"},{"label":"首个字段","value":"Byte1('T')"}],"fields":[{"description":"Identifies the message as a truncate message.","format":"Byte1('T')"},{"description":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.","format":"Int32 (TransactionId)"},{"description":"Number of relations","format":"Int32"},{"description":"Option bits for TRUNCATE : 1 for CASCADE , 2 for RESTART IDENTITY","format":"Int8"},{"description":"OID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.","format":"Int32 (Oid)"}],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('T')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a truncate message.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32 (TransactionId)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eXid of the transaction (only present for streamed transactions). This field is available since protocol version 2.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eNumber of relations\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOption bits for \u003ccode class=\"command\"\u003eTRUNCATE\u003c/code\u003e: 1 for \u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e, 2 for \u003ccode class=\"literal\"\u003eRESTART IDENTITY\u003c/code\u003e\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32 (Oid)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003c/dd\u003e\u003c/dl\u003e","manual_path":"/docs/18/protocol-logicalrep-message-formats.html","related":[{"label":"Streaming replication protocol","url":"/docs/18/protocol-replication.html"},{"label":"Logical Decoding Plugins","url":"/wiki/decode/?v=18"}],"release":{"channel":"stable","label":"18.6","major":"18","ref":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2","revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"},"sections":[{"paragraphs":["This section describes the detailed format of each logical replication message. These messages are either returned by the replication slot SQL interface or are sent by a walsender. In the case of a walsender, they are encapsulated inside replication protocol WAL messages as described in Section 54.4 , and generally obey the same message flow as physical replication. The following messages (Stream Start, Stream Stop, Stream Commit, and Stream Abort) are available since protocol version 2. The following messages (Begin Prepare, Prepare, Commit Prepared, Rollback Prepared, Stream Prepare) are available since protocol version 3. The following message parts are shared by the above messages."],"title":"Protocol context"}],"sections_zh":[{"paragraphs":["本节说明各逻辑复制消息的详细格式。这些消息由复制槽 SQL 接口返回，或由 walsender 发送。由 walsender 发送时，它们被封装在复制协议的 WAL 消息中（参见第 54.4 节），消息流程通常与物理复制相同。Stream Start、Stream Stop、Stream Commit 和 Stream Abort 从协议版本 2 起可用。Begin Prepare、Prepare、Commit Prepared、Rollback Prepared 和 Stream Prepare 从协议版本 3 起可用。以下消息部分为上述消息所共用。"],"title":"协议上下文"}],"signature":"Truncate","sources":[{"label":"PostgreSQL 18 English manual","path":"protocol-logicalrep-message-formats.html","sha256":"e976b008206820fbeb1eba226e69bb7c00af157372c3545375d1b5053c76d0ad","url":"/docs/18/protocol-logicalrep-message-formats.html#PROTOCOL-LOGICALREP-MESSAGE-FORMATS-TRUNCATE"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Byte1('T')","c2":"Identifies the message as a truncate message."},{"c0":"2","c1":"Int32 (TransactionId)","c2":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2."},{"c0":"3","c1":"Int32","c2":"Number of relations"},{"c0":"4","c1":"Int8","c2":"Option bits for TRUNCATE : 1 for CASCADE , 2 for RESTART IDENTITY"},{"c0":"5","c1":"Int32 (Oid)","c2":"OID of the relation corresponding to the ID in the relation message. This field is repeated for each relation."}],"title":"Fields in documented order"}],"tables_zh":[{"columns":[{"key":"c0","label":"位置"},{"key":"c1","label":"格式"},{"key":"c2","label":"含义"}],"key":"fields","rows":[{"c0":"1","c1":"Byte1('T')","c2":"将该消息标识为 Truncate 消息。"},{"c0":"2","c1":"Int32 (TransactionId)","c2":"事务的 XID，仅在流式传输事务中出现。此字段从协议版本 2 起可用。"},{"c0":"3","c1":"Int32","c2":"关系数量"},{"c0":"4","c1":"Int8","c2":"TRUNCATE 的选项位：1 表示 CASCADE，2 表示 RESTART IDENTITY"},{"c0":"5","c1":"Int32 (Oid)","c2":"关系的 OID，与 Relation 消息中的 ID 对应。每个关系都重复出现此字段。"}],"title":"按手册顺序排列的字段"}],"zh_from":{"authored_translation":"source-derived-identity","body_sha256":"5ea85a87ac8cde53cefdc5e181988a3cf8083c6f5169867ab5c9a114b9eb561e","kind":"same-version-chinese-manual-with-source-derived-identity","manual":{"anchor":"PROTOCOL-LOGICALREP-MESSAGE-FORMATS-TRUNCATE","build_id":107,"extraction":"exact-definition","fragment_sha256":"0be4ad0c0c9675995329ea83078745e0ed319236f5b1463bc29570cf08b29db1","locale":"zh-Hans","page_key":"protocol-logicalrep-message-formats.html","source_hash":"9561d3a39aca911a61b68b188aa97828e60fb6f7d81323d8aada08fe67259039","source_revision":"unknown:rendered-translation-baseline","translated_from_revision":null,"translation_revision":"git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:08e987a66af27b98444a8057c256314eafa13611a3fb9e888214fc436824244b","url":"/zh/docs/18/protocol-logicalrep-message-formats.html#PROTOCOL-LOGICALREP-MESSAGE-FORMATS-TRUNCATE","version":"18"},"runtime_rerun":false,"source_facts_revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}},"ManualEvidence":{"manual_path":"/docs/18/protocol-logicalrep-message-formats.html","release":{"channel":"stable","label":"18.6","major":"18","ref":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2","revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"},"sources":[{"label":"PostgreSQL 18 English manual","path":"protocol-logicalrep-message-formats.html","sha256":"e976b008206820fbeb1eba226e69bb7c00af157372c3545375d1b5053c76d0ad","url":"/docs/18/protocol-logicalrep-message-formats.html#PROTOCOL-LOGICALREP-MESSAGE-FORMATS-TRUNCATE"}]},"MeasuredEvidence":{}},"Text":{"Collection":"protocol","Key":"logical-truncate","SourceDatabase":"center","Version":"18","Locale":"en","Title":"Truncate (logical replication)","Summary":"Logical replication Truncate format. Identifies the message as a truncate message.","BodyHTML":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cspan\u003eByte1(\u0026#39;T\u0026#39;)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a truncate message.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32 (TransactionId)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eXid of the transaction (only present for streamed transactions). This field is available since protocol version 2.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eNumber of relations\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOption bits for \u003ccode\u003eTRUNCATE\u003c/code\u003e: 1 for \u003ccode\u003eCASCADE\u003c/code\u003e, 2 for \u003ccode\u003eRESTART IDENTITY\u003c/code\u003e\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32 (Oid)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003c/dd\u003e\u003c/dl\u003e","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","ContentHash":"862bea2fd0a9bfb51ddc6ae795502304e494a7cab829c65f36608030d74dfceb","Payload":{"description":["Logical replication Truncate format. Identifies the message as a truncate message."],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('T')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a truncate message.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32 (TransactionId)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eXid of the transaction (only present for streamed transactions). This field is available since protocol version 2.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eNumber of relations\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOption bits for \u003ccode class=\"command\"\u003eTRUNCATE\u003c/code\u003e: 1 for \u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e, 2 for \u003ccode class=\"literal\"\u003eRESTART IDENTITY\u003c/code\u003e\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32 (Oid)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003c/dd\u003e\u003c/dl\u003e","related":[{"label":"Streaming replication protocol","url":"/docs/18/protocol-replication.html"},{"label":"Logical Decoding Plugins","url":"/wiki/decode/?v=18"}],"sections":[{"paragraphs":["This section describes the detailed format of each logical replication message. These messages are either returned by the replication slot SQL interface or are sent by a walsender. In the case of a walsender, they are encapsulated inside replication protocol WAL messages as described in Section 54.4 , and generally obey the same message flow as physical replication. The following messages (Stream Start, Stream Stop, Stream Commit, and Stream Abort) are available since protocol version 2. The following messages (Begin Prepare, Prepare, Commit Prepared, Rollback Prepared, Stream Prepare) are available since protocol version 3. The following message parts are shared by the above messages."],"title":"Protocol context"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Byte1('T')","c2":"Identifies the message as a truncate message."},{"c0":"2","c1":"Int32 (TransactionId)","c2":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2."},{"c0":"3","c1":"Int32","c2":"Number of relations"},{"c0":"4","c1":"Int8","c2":"Option bits for TRUNCATE : 1 for CASCADE , 2 for RESTART IDENTITY"},{"c0":"5","c1":"Int32 (Oid)","c2":"OID of the relation corresponding to the ID in the relation message. This field is repeated for each relation."}],"title":"Fields in documented order"}]}},"RequestedLocale":"en","Fallback":false,"Versions":["11","12","13","14","15","16","17","18","19","20"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}