{"Entry":{"collection":"protocol","key":"logical-relation","name":"Relation (logical replication)","aliases":["Relation"],"metadata":{"aliases":["Relation"],"category":"Logical replication formats","content_hash":"8de3e5c48a9047bf2cfc3c66cacd64afd0aa27b55de8dcce20975dd6f50ebfec","derived_content_hash":"8c126ab63c6189769914b00f4147c564d9aa58913ea4dc5b42c3a6faab9e42e0","imported_at":"2026-09-30T00:40:44.638614+08:00","name":"Relation (logical replication)","name_zh":"","slug":"logical-relation","summary":"Logical replication Relation format. Identifies the message as a relation message."}},"Definition":{"Collection":"protocol","Key":"logical-relation","SourceDatabase":"center","Version":"18","SourceTable":"protocol_message","SourceKey":"logical-relation","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","Facts":{"comparison_data":{"fields":[{"description":"Identifies the message as a relation message.","format":"Byte1('R')"},{"description":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.","format":"Int32 (TransactionId)"},{"description":"OID of the relation.","format":"Int32 (Oid)"},{"description":"Namespace (empty string for pg_catalog ).","format":"String"},{"description":"Relation name.","format":"String"},{"description":"Replica identity setting for the relation (same as relreplident in pg_class ).","format":"Int8"},{"description":"Number of columns.","format":"Int16"},{"description":"Flags for the column. Currently can be either 0 for no flags or 1 which marks the column as part of the key.","format":"Int8"},{"description":"Name of the column.","format":"String"},{"description":"OID of the column's data type.","format":"Int32 (Oid)"},{"description":"Type modifier of the column ( atttypmod ).","format":"Int32"}],"layer":"logical replication"},"comparison_hash":"e38e342bd63afe84c580ef245a7f6c70b95b32928e766a86e51f9732fd2569b4","description":["Logical replication Relation format. Identifies the message as a relation message."],"description_zh":"Byte1('R') 将该消息标识为 Relation 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 (Oid) 关系的 OID。 String 命名空间（对于 pg_catalog 为空字符串）。 String 关系名称。 Int8 关系的复制标识设置（与 pg_class 中的 relreplident 相同）。 Int16 列数。 接下来，发布中包含的每一列都会出现以下消息部分： Int8 列的标志。目前可以为 0，表示没有标志；或为 1，标记该列是键的一部分。 String 列的名称。 Int32 (Oid) 列数据类型的 OID。 Int32 列的类型修饰符（ atttypmod ）。","description_zh_html":"\u003cp\u003e协议消息 Relation。\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('R')\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         将该消息标识为 Relation 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 (Oid)\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         关系的 OID。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eString\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         命名空间（对于 \u003ccode class=\"literal\"\u003epg_catalog\u003c/code\u003e 为空字符串）。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eString\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         关系名称。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt8\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         关系的复制标识设置（与 \u003ccode class=\"structname\"\u003epg_class\u003c/code\u003e 中的 \u003ccode class=\"structfield\"\u003erelreplident\u003c/code\u003e 相同）。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt16\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         列数。\n        \u003c/p\u003e\u003c/dd\u003e\u003c/dl\u003e\u003c/div\u003e\u003cp\u003e\n      接下来，发布中包含的每一列都会出现以下消息部分：\n     \u003c/p\u003e\u003cdiv class=\"variablelist\"\u003e\u003cdl class=\"variablelist\"\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt8\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         列的标志。目前可以为 0，表示没有标志；或为 1，标记该列是键的一部分。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eString\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         列的名称。\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         列数据类型的 OID。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         列的类型修饰符（\u003ccode class=\"structfield\"\u003eatttypmod\u003c/code\u003e）。\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-RELATION\"\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('R')"}],"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('R')"}],"fields":[{"description":"Identifies the message as a relation message.","format":"Byte1('R')"},{"description":"Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.","format":"Int32 (TransactionId)"},{"description":"OID of the relation.","format":"Int32 (Oid)"},{"description":"Namespace (empty string for pg_catalog ).","format":"String"},{"description":"Relation name.","format":"String"},{"description":"Replica identity setting for the relation (same as relreplident in pg_class ).","format":"Int8"},{"description":"Number of columns.","format":"Int16"},{"description":"Flags for the column. Currently can be either 0 for no flags or 1 which marks the column as part of the key.","format":"Int8"},{"description":"Name of the column.","format":"String"},{"description":"OID of the column's data type.","format":"Int32 (Oid)"},{"description":"Type modifier of the column ( atttypmod ).","format":"Int32"}],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('R')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a relation 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 (Oid)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOID of the relation.\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\u003eNamespace (empty string for \u003ccode class=\"literal\"\u003epg_catalog\u003c/code\u003e).\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\u003eRelation name.\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\u003eReplica identity setting for the relation (same as \u003ccode class=\"structfield\"\u003erelreplident\u003c/code\u003e in \u003ccode class=\"structname\"\u003epg_class\u003c/code\u003e).\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt16\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eNumber of columns.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eNext, the following message part appears for each column included in the publication:\u003c/p\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eFlags for the column. Currently can be either 0 for no flags or 1 which marks the column as part of the key.\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\u003eName of the column.\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 column's data type.\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\u003eType modifier of the column (\u003ccode class=\"structfield\"\u003eatttypmod\u003c/code\u003e).\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":"Relation","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-RELATION"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Byte1('R')","c2":"Identifies the message as a relation 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 (Oid)","c2":"OID of the relation."},{"c0":"4","c1":"String","c2":"Namespace (empty string for pg_catalog )."},{"c0":"5","c1":"String","c2":"Relation name."},{"c0":"6","c1":"Int8","c2":"Replica identity setting for the relation (same as relreplident in pg_class )."},{"c0":"7","c1":"Int16","c2":"Number of columns."},{"c0":"8","c1":"Int8","c2":"Flags for the column. Currently can be either 0 for no flags or 1 which marks the column as part of the key."},{"c0":"9","c1":"String","c2":"Name of the column."},{"c0":"10","c1":"Int32 (Oid)","c2":"OID of the column's data type."},{"c0":"11","c1":"Int32","c2":"Type modifier of the column ( atttypmod )."}],"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('R')","c2":"将该消息标识为 Relation 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 (Oid)","c2":"关系的OID。"},{"c0":"4","c1":"字符串","c2":"命名空间（对于 pg_catalog 为空字符串）。"},{"c0":"5","c1":"字符串","c2":"关系名称。"},{"c0":"6","c1":"Int8","c2":"关系的复制标识设置，与 pg_class 中的 relreplident 相同。"},{"c0":"7","c1":"Int16","c2":"列数。"},{"c0":"8","c1":"Int8","c2":"列的标志。目前可以为 0，表示没有标志；或为 1，标记该列是键的一部分。"},{"c0":"9","c1":"字符串","c2":"列的名称。"},{"c0":"10","c1":"Int32 (Oid)","c2":"列数据类型的OID。"},{"c0":"11","c1":"Int32","c2":"列的类型修饰符（ atttypmod ）。"}],"title":"按手册顺序排列的字段"}],"zh_from":{"authored_translation":"source-derived-identity","body_sha256":"2d9c7370e35322e4b52dd18e88c20379598dee95351e7f9e530bd0f757d19f5b","kind":"same-version-chinese-manual-with-source-derived-identity","manual":{"anchor":"PROTOCOL-LOGICALREP-MESSAGE-FORMATS-RELATION","build_id":107,"extraction":"exact-definition","fragment_sha256":"460d7f78c7377c914553b4ff3152fb6b7e4831d5dca88fca64471cc4d4baa99b","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-RELATION","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-RELATION"}]},"MeasuredEvidence":{}},"Text":{"Collection":"protocol","Key":"logical-relation","SourceDatabase":"center","Version":"18","Locale":"en","Title":"Relation (logical replication)","Summary":"Logical replication Relation format. Identifies the message as a relation message.","BodyHTML":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cspan\u003eByte1(\u0026#39;R\u0026#39;)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a relation 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 (Oid)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOID of the relation.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eString\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eNamespace (empty string for \u003ccode\u003epg_catalog\u003c/code\u003e).\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eString\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eRelation name.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eReplica identity setting for the relation (same as \u003ccode\u003erelreplident\u003c/code\u003e in \u003ccode\u003epg_class\u003c/code\u003e).\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt16\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eNumber of columns.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eNext, the following message part appears for each column included in the publication:\u003c/p\u003e\n\u003cdiv\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cspan\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eFlags for the column. Currently can be either 0 for no flags or 1 which marks the column as part of the key.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eString\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eName of the column.\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 column\u0026#39;s data type.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eType modifier of the column (\u003ccode\u003eatttypmod\u003c/code\u003e).\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":"a456dea01de63d22d1688ffb9f57465ed9e0671afb1be5dce9945fdf5b1fe5e8","Payload":{"description":["Logical replication Relation format. Identifies the message as a relation message."],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('R')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a relation 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 (Oid)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eOID of the relation.\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\u003eNamespace (empty string for \u003ccode class=\"literal\"\u003epg_catalog\u003c/code\u003e).\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\u003eRelation name.\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\u003eReplica identity setting for the relation (same as \u003ccode class=\"structfield\"\u003erelreplident\u003c/code\u003e in \u003ccode class=\"structname\"\u003epg_class\u003c/code\u003e).\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt16\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eNumber of columns.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eNext, the following message part appears for each column included in the publication:\u003c/p\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt8\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eFlags for the column. Currently can be either 0 for no flags or 1 which marks the column as part of the key.\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\u003eName of the column.\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 column's data type.\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\u003eType modifier of the column (\u003ccode class=\"structfield\"\u003eatttypmod\u003c/code\u003e).\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('R')","c2":"Identifies the message as a relation 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 (Oid)","c2":"OID of the relation."},{"c0":"4","c1":"String","c2":"Namespace (empty string for pg_catalog )."},{"c0":"5","c1":"String","c2":"Relation name."},{"c0":"6","c1":"Int8","c2":"Replica identity setting for the relation (same as relreplident in pg_class )."},{"c0":"7","c1":"Int16","c2":"Number of columns."},{"c0":"8","c1":"Int8","c2":"Flags for the column. Currently can be either 0 for no flags or 1 which marks the column as part of the key."},{"c0":"9","c1":"String","c2":"Name of the column."},{"c0":"10","c1":"Int32 (Oid)","c2":"OID of the column's data type."},{"c0":"11","c1":"Int32","c2":"Type modifier of the column ( atttypmod )."}],"title":"Fields in documented order"}]}},"RequestedLocale":"en","Fallback":false,"Versions":["10","11","12","13","14","15","16","17","18","19","20"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}