Begin Prepare (logical replication)

Logical replication Begin Prepare format. Identifies the message as the beginning of a prepared transaction message.

Reading PG 18·Select a recorded version

Layer: Logical replication payload; distinct from the frontend/backend message envelope
First field: Byte1('b')
manual path: /docs/18/protocol-logicalrep-message-formats.html
signature: Begin Prepare

Definition PG 18

Byte1('b'): Identifies the message as the beginning of a prepared transaction message.
Int64 (XLogRecPtr): The LSN of the prepare.
Int64 (XLogRecPtr): The end LSN of the prepared transaction.
Int64 (TimestampTz): Prepare 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.

Fields in documented order

Position	Format	Meaning
1	Byte1('b')	Identifies the message as the beginning of a prepared transaction message.
2	Int64 (XLogRecPtr)	The LSN of the prepare.
3	Int64 (XLogRecPtr)	The end LSN of the prepared transaction.
4	Int64 (TimestampTz)	Prepare timestamp of the transaction. The value is in number of microseconds since PostgreSQL epoch (2000-01-01).
5	Int32 (TransactionId)	Xid of the transaction.
6	String	The user defined GID of the prepared transaction.

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Complete source facts

fields

map[description:Identifies the message as the beginning of a prepared transaction message. format:Byte1('b')], map[description:The LSN of the prepare. format:Int64 (XLogRecPtr)], map[description:The end LSN of the prepared transaction. format:Int64 (XLogRecPtr)], map[description:Prepare timestamp of the transaction. The value is in number of microseconds since PostgreSQL epoch (2000-01-01). format:Int64 (TimestampTz)], map[description:Xid of the transaction. format:Int32 (TransactionId)], map[description:The user defined GID of the prepared transaction. format:String]

Source references

Full definition and evidence JSON

Definition sources

center · PostgreSQL 18 · 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f