Wiki / Protocol Messages / Logical replication formats
Commit Prepared (logical replication)
Logical replication Commit Prepared format. Identifies the message as the commit of a prepared transaction message.
Reading PostgreSQL 18.6.
Description
Logical replication Commit Prepared format. Identifies the message as the commit of a prepared transaction message.
- Layer
- Logical replication payload; distinct from the frontend/backend message envelope
- First field
- Byte1('K')
Usage
Commit PreparedProtocol 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.
Fields in documented order
| Position | Format | Meaning |
|---|---|---|
| 1 | Byte1('K') | Identifies the message as the commit of a prepared transaction message. |
| 2 | Int8(0) | Flags; currently unused. |
| 3 | Int64 (XLogRecPtr) | The LSN of the commit of the prepared transaction. |
| 4 | Int64 (XLogRecPtr) | The end LSN of the commit of the prepared transaction. |
| 5 | Int64 (TimestampTz) | Commit timestamp of the transaction. The value is in number of microseconds since PostgreSQL epoch (2000-01-01). |
| 6 | Int32 (TransactionId) | Xid of the transaction. |
| 7 | String | The user defined GID of the prepared transaction. |
Manual definition
-
- Byte1('K')
-
Identifies the message as the commit of a prepared transaction message.
- Int8(0)
-
Flags; currently unused.
- Int64 (XLogRecPtr)
-
The LSN of the commit of the prepared transaction.
- Int64 (XLogRecPtr)
-
The end LSN of the commit of the prepared transaction.
- Int64 (TimestampTz)
-
Commit timestamp of the transaction. The value is in number of microseconds since PostgreSQL epoch (2000-01-01).
- Int32 (TransactionId)
-
Xid of the transaction.
- String
-
The user defined GID of the prepared transaction.
Related entries
Documentation and source
Source build
- Version
- 18.6
- Build
- https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2
- Source fingerprint
555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f
Compare versions
PostgreSQL 17 → 18: unchanged.
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)Delete (logical replication)Insert (logical replication)Message (logical replication)Origin (logical replication)Prepare (logical replication)Relation (logical replication)Rollback Prepared (logical replication)Stream Abort (logical replication)Stream Commit (logical replication)
Export JSON · Back to Protocol Messages · Recorded in PostgreSQL 15 through 20; the first sample is not necessarily its introduction.