{"Entry":{"collection":"protocol","key":"logical-truncate","name":"Truncate (logical replication)","aliases":["Truncate"],"metadata":{"aliases":["Truncate"],"category":"Logical replication formats","content_hash":"f026ebf95e4a9fb0711de41ccd64e6b914eb41f4f600c7ee984bb7996d12176c","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."],"facts":[{"label":"Layer","value":"Logical replication payload; distinct from the frontend/backend message envelope"},{"label":"First field","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"}],"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"}]},"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":"zh-Hans","Fallback":true,"Versions":["11","12","13","14","15","16","17","18","19","20"],"Locales":["en"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}