Wiki / Statistics & Metrics / pg_stat_io
pg_stat_io.writebacks
Number of units of size BLCKSZ (typically 8kB) which the process requested the kernel write out to permanent storage.
Reading PostgreSQL 18.6.
Description
Number of units of size BLCKSZ (typically 8kB) which the process requested the kernel write out to permanent storage.
- View
- pg_stat_io
- Field
- writebacks
- SQL type
- bigint
- Units named in the field definition
- Not specified
- Reset observation
- Time at which these statistics were last reset.
Usage
SELECT writebacks FROM pg_catalog.pg_stat_io;View semantics
The pg_stat_io view will contain one row for each combination of backend type, target I/O object, and I/O context, showing cluster-wide I/O statistics. Combinations which do not make sense are omitted. Currently, I/O on relations (e.g. tables, indexes) and WAL activity are tracked. However, relation I/O which bypasses shared buffers (e.g. when moving a table from one tablespace to another) is currently not tracked.
Collection and reset context
Read the same-version statistics collection and view documentation below for reset scope and visibility. No per-field reset rule is inferred from the field name.
Inspect this field
Example query; no execution result or measured value is asserted.
SELECT writebacks FROM pg_catalog.pg_stat_io;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 15 → 16: added.
--- PostgreSQL 15
+++ PostgreSQL 16
@@ -1 +1,6 @@
-Not recorded in this version
+{
+ "field": "writebacks",
+ "sql_type": "bigint",
+ "units_mentioned": [],
+ "view": "pg_stat_io"
+}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 Statistics & Metrics · Recorded in PostgreSQL 16 through 20; the first sample is not necessarily its introduction.