{"Entry":{"collection":"protocol","key":"logical-message","name":"Message (logical replication)","aliases":["Message"],"metadata":{"aliases":["Message"],"category":"Logical replication formats","content_hash":"e114c30bf2387ec527579106b85601dc78f7a1f4772442c48b9142cad12b34bc","derived_content_hash":"cc38bbd27e1bfbbc36893cb7c1e217ea021b29f2d8e489643437d531498f16f0","imported_at":"2026-09-30T00:40:44.626465+08:00","name":"Message (logical replication)","name_zh":"","slug":"logical-message","summary":"Logical replication Message format. Identifies the message as a logical decoding message."}},"Definition":{"Collection":"protocol","Key":"logical-message","SourceDatabase":"center","Version":"18","SourceTable":"protocol_message","SourceKey":"logical-message","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","Facts":{"comparison_data":{"fields":[{"description":"Identifies the message as a logical decoding message.","format":"Byte1('M')"},{"description":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.","format":"Int32 (TransactionId)"},{"description":"Flags; Either 0 for no flags or 1 if the logical decoding message is transactional.","format":"Int8"},{"description":"The LSN of the logical decoding message.","format":"Int64 (XLogRecPtr)"},{"description":"The prefix of the logical decoding message.","format":"String"},{"description":"Length of the content.","format":"Int32"},{"description":"The content of the logical decoding message.","format":"Byte n"}],"layer":"logical replication"},"comparison_hash":"e342b37109a65064e914f18c92934727892fb2c60c929fa2221ad41dfbb7dbb8","description":["Logical replication Message format. Identifies the message as a logical decoding message."],"description_zh":"Byte1('M') 将消息标识为逻辑解码消息。 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。 Int8 标志：0 表示没有标志；1 表示该逻辑解码消息是事务性的。 Int64 (XLogRecPtr) 逻辑解码消息的 LSN。 String 逻辑解码消息的前缀。 Int32 内容的长度。 Byte n 逻辑解码消息的内容。","description_zh_html":"\u003cp\u003e协议消息 Message。\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('M')\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         将消息标识为逻辑解码消息。\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\"\u003eInt8\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         标志：0 表示没有标志；1 表示该逻辑解码消息是事务性的。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt64 (XLogRecPtr)\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         逻辑解码消息的 LSN。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eString\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         逻辑解码消息的前缀。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         内容的长度。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eByte\u003cem class=\"replaceable\"\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         逻辑解码消息的内容。\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-MESSAGE\"\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('M')"}],"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('M')"}],"fields":[{"description":"Identifies the message as a logical decoding message.","format":"Byte1('M')"},{"description":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.","format":"Int32 (TransactionId)"},{"description":"Flags; Either 0 for no flags or 1 if the logical decoding message is transactional.","format":"Int8"},{"description":"The LSN of the logical decoding message.","format":"Int64 (XLogRecPtr)"},{"description":"The prefix of the logical decoding message.","format":"String"},{"description":"Length of the content.","format":"Int32"},{"description":"The content of the logical decoding message.","format":"Byte n"}],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('M')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a logical decoding 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\"\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eFlags; Either 0 for no flags or 1 if the logical decoding message is transactional.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt64 (XLogRecPtr)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe LSN of the logical decoding message.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eString\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe prefix of the logical decoding message.\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\u003eLength of the content.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte\u003cem class=\"replaceable\"\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe content of the logical decoding message.\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":"Message","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-MESSAGE"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Byte1('M')","c2":"Identifies the message as a logical decoding 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":"Int8","c2":"Flags; Either 0 for no flags or 1 if the logical decoding message is transactional."},{"c0":"4","c1":"Int64 (XLogRecPtr)","c2":"The LSN of the logical decoding message."},{"c0":"5","c1":"String","c2":"The prefix of the logical decoding message."},{"c0":"6","c1":"Int32","c2":"Length of the content."},{"c0":"7","c1":"Byte n","c2":"The content of the logical decoding message."}],"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('M')","c2":"将消息标识为逻辑解码消息。"},{"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":"Int8","c2":"标志：0 表示没有标志；1 表示该逻辑解码消息是事务性的。"},{"c0":"4","c1":"Int64 (XLogRecPtr)","c2":"逻辑解码消息的LSN。"},{"c0":"5","c1":"字符串","c2":"逻辑解码消息的前缀。"},{"c0":"6","c1":"Int32","c2":"内容的长度。"},{"c0":"7","c1":"Byte n","c2":"逻辑解码消息的内容。"}],"title":"按手册顺序排列的字段"}],"zh_from":{"authored_translation":"source-derived-identity","body_sha256":"ce8b49aaf58e3f8b225a0d9fa1b4da32c6635f8bdd95ac1d0c8995702a539295","kind":"same-version-chinese-manual-with-source-derived-identity","manual":{"anchor":"PROTOCOL-LOGICALREP-MESSAGE-FORMATS-MESSAGE","build_id":107,"extraction":"exact-definition","fragment_sha256":"d10861fdd318320079d5043fd35131a2df816daf03223da60b986c6dca4dd1cf","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-MESSAGE","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-MESSAGE"}]},"MeasuredEvidence":{}},"Text":{"Collection":"protocol","Key":"logical-message","SourceDatabase":"center","Version":"18","Locale":"en","Title":"Message (logical replication)","Summary":"Logical replication Message format. Identifies the message as a logical decoding message.","BodyHTML":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cspan\u003eByte1(\u0026#39;M\u0026#39;)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a logical decoding 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\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eFlags; Either 0 for no flags or 1 if the logical decoding message is transactional.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt64 (XLogRecPtr)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe LSN of the logical decoding message.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eString\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe prefix of the logical decoding message.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eLength of the content.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eByte\u003cem\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe content of the logical decoding message.\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":"edc4e43b3aa37ff94c85d35d75f1a7f69627de94dbfdb971e0004f0b8d1ccc47","Payload":{"description":["Logical replication Message format. Identifies the message as a logical decoding message."],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('M')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a logical decoding 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\"\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eFlags; Either 0 for no flags or 1 if the logical decoding message is transactional.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt64 (XLogRecPtr)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe LSN of the logical decoding message.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eString\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe prefix of the logical decoding message.\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\u003eLength of the content.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte\u003cem class=\"replaceable\"\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe content of the logical decoding message.\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('M')","c2":"Identifies the message as a logical decoding 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":"Int8","c2":"Flags; Either 0 for no flags or 1 if the logical decoding message is transactional."},{"c0":"4","c1":"Int64 (XLogRecPtr)","c2":"The LSN of the logical decoding message."},{"c0":"5","c1":"String","c2":"The prefix of the logical decoding message."},{"c0":"6","c1":"Int32","c2":"Length of the content."},{"c0":"7","c1":"Byte n","c2":"The content of the logical decoding message."}],"title":"Fields in documented order"}]}},"RequestedLocale":"en","Fallback":false,"Versions":["14","15","16","17","18","19","20"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}