Wiki / Protocol Messages / Backend messages
ReadyForQuery
ReadyForQuery is a backend protocol message. Identifies the message type. ReadyForQuery is sent whenever the backend is ready for a new query cycle.
Reading PostgreSQL 18.6.
Description
ReadyForQuery is a backend protocol message. Identifies the message type. ReadyForQuery is sent whenever the backend is ready for a new query cycle.
- Direction
- Backend → frontend
- First wire field
- Byte1('Z')
- Field entries
- 3
- Documented flow contexts
- Start-up; Simple Query; Extended Query; Pipelining; Function Call; COPY Operations; Asynchronous Operations
Usage
ReadyForQuery (B)Framing and repetition
The complete definition below retains repetition, counts and conditional fields. A numbered table row is a documented field definition, not a fixed byte offset. Integer encodings and flow rules follow the same-version protocol chapter.
Wire fields in documented order
| Position | Format | Meaning |
|---|---|---|
| 1 | Byte1('Z') | Identifies the message type. ReadyForQuery is sent whenever the backend is ready for a new query cycle. |
| 2 | Int32(5) | Length of message contents in bytes, including self. |
| 3 | Byte1 | Current backend transaction status indicator. Possible values are ' I ' if idle (not in a transaction block); ' T ' if in a transaction block; or ' E ' if in a failed transaction block (queries will be rejected until block is ended). |
Manual definition
-
- Byte1('Z')
-
Identifies the message type. ReadyForQuery is sent whenever the backend is ready for a new query cycle.
- Int32(5)
-
Length of message contents in bytes, including self.
- Byte1
-
Current backend transaction status indicator. Possible values are '
I' if idle (not in a transaction block); 'T' if in a transaction block; or 'E' if in a failed transaction block (queries will be rejected until block is ended).
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
Export JSON · Back to Protocol Messages · Recorded in PostgreSQL 10 through 20; the first sample is not necessarily its introduction.