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Wiki / Protocol Messages / Logical replication formats

Truncate (logical replication)

Logical replication Truncate format. Identifies the message as a truncate message.

Reading PostgreSQL 18.6.

Description

Logical replication Truncate format. Identifies the message as a truncate message.

Layer
Logical replication payload; distinct from the frontend/backend message envelope
First field
Byte1('T')

Usage

Truncate

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.

Fields in documented order

PositionFormatMeaning
1Byte1('T')Identifies the message as a truncate message.
2Int32 (TransactionId)Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.
3Int32Number of relations
4Int8Option bits for TRUNCATE : 1 for CASCADE , 2 for RESTART IDENTITY
5Int32 (Oid)OID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.

Manual definition

Byte1('T')

Identifies the message as a truncate message.

Int32 (TransactionId)

Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2.

Int32

Number of relations

Int8

Option bits for TRUNCATE: 1 for CASCADE, 2 for RESTART IDENTITY

Int32 (Oid)

OID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.

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 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": "Number of relations",
@@ -17,8 +17,8 @@
       "format": "Int8"
     },
     {
-      "description": "ID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.",
-      "format": "Int32"
+      "description": "OID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.",
+      "format": "Int32 (Oid)"
     }
   ],
   "layer": "logical replication"

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

Export JSON · Back to Protocol Messages · Recorded in PostgreSQL 11 through 20; the first sample is not necessarily its introduction.