Message (logical replication)

Description

Logical replication Message format. Identifies the message as a logical decoding message.

Layer

Logical replication payload; distinct from the frontend/backend message envelope

First field

Byte1('M')

Usage

Message

Protocol context

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.

Related entries

• Streaming replication protocol
• Logical Decoding Plugins

Documentation and source

• PostgreSQL 18 English manual

Compare versions

PostgreSQL 14 → 15: changed.

--- PostgreSQL 14
+++ PostgreSQL 15
@@ -6,7 +6,7 @@
     },
     {
       "description": "Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.",
-      "format": "Int32"
+      "format": "Int32 (TransactionId)"
     },
     {
       "description": "Flags; Either 0 for no flags or 1 if the logical decoding message is transactional.",
@@ -14,7 +14,7 @@
     },
     {
       "description": "The LSN of the logical decoding message.",
-      "format": "Int64"
+      "format": "Int64 (XLogRecPtr)"
     },
     {
       "description": "The prefix of the logical decoding message.",

Compares recorded interfaces and attributes. Source fingerprints and build metadata are excluded; an absent sample is not proof of the introduction or removal release.

Related entries

• Begin (logical replication)
• Begin Prepare (logical replication)
• Commit (logical replication)
• Commit Prepared (logical replication)
• Delete (logical replication)
• Insert (logical replication)
• Origin (logical replication)
• Prepare (logical replication)
• Relation (logical replication)
• Rollback Prepared (logical replication)
• Stream Abort (logical replication)
• Stream Commit (logical replication)