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
TruncateProtocol 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('T') | Identifies the message as a truncate message. |
| 2 | Int32 (TransactionId) | Xid of the transaction (only present for streamed transactions). This field is available since protocol version 2. |
| 3 | Int32 | Number of relations |
| 4 | Int8 | Option bits for TRUNCATE : 1 for CASCADE , 2 for RESTART IDENTITY |
| 5 | Int32 (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 forCASCADE, 2 forRESTART 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 10 → 11: added.
--- PostgreSQL 10
+++ PostgreSQL 11
@@ -1 +1,21 @@
-Not recorded in this version
+{
+ "fields": [
+ {
+ "description": "Identifies the message as a truncate message.",
+ "format": "Byte1('T')"
+ },
+ {
+ "description": "Number of relations",
+ "format": "Int32"
+ },
+ {
+ "description": "Option bits for TRUNCATE : 1 for CASCADE , 2 for RESTART IDENTITY",
+ "format": "Int8"
+ },
+ {
+ "description": "ID of the relation corresponding to the ID in the relation message. This field is repeated for each relation.",
+ "format": "Int32"
+ }
+ ],
+ "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
Begin (logical replication)Begin Prepare (logical replication)Commit (logical replication)Commit Prepared (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)
Export JSON · Back to Protocol Messages · Recorded in PostgreSQL 11 through 20; the first sample is not necessarily its introduction.