pg_stat_slru
A statistics view displaying information about access to cached pages
pg_stat_slru is a statistics view displaying information about access to cached pages. Specifically it provides a way of monitoring various lesser caches which use the SLRU (simple least-recently-used) algorithm for cache eviction, and is initially intended to assist with development and benchmarking.
pg_stat_slru was added in PostgreSQL 13.
Statistics reset
The statistics displayed by pg_stat_slru can be reset by executing:
SELECT pg_stat_reset_slru()
Definition by PostgreSQL version
pg_stat_slru (PostgreSQL 15)
View "pg_catalog.pg_stat_slru"
Column | Type | Collation | Nullable | Default
--------------+--------------------------+-----------+----------+---------
name | text | | |
blks_zeroed | bigint | | |
blks_hit | bigint | | |
blks_read | bigint | | |
blks_written | bigint | | |
blks_exists | bigint | | |
flushes | bigint | | |
truncates | bigint | | |
stats_reset | timestamp with time zone | | |
Documentation: pg_stat_slru
pg_stat_slru (PostgreSQL 14)
View "pg_catalog.pg_stat_slru"
Column | Type | Collation | Nullable | Default
--------------+--------------------------+-----------+----------+---------
name | text | | |
blks_zeroed | bigint | | |
blks_hit | bigint | | |
blks_read | bigint | | |
blks_written | bigint | | |
blks_exists | bigint | | |
flushes | bigint | | |
truncates | bigint | | |
stats_reset | timestamp with time zone | | |
Documentation: pg_stat_slru
pg_stat_slru (PostgreSQL 13)
View "pg_catalog.pg_stat_slru"
Column | Type | Collation | Nullable | Default
--------------+--------------------------+-----------+----------+---------
name | text | | |
blks_zeroed | bigint | | |
blks_hit | bigint | | |
blks_read | bigint | | |
blks_written | bigint | | |
blks_exists | bigint | | |
flushes | bigint | | |
truncates | bigint | | |
stats_reset | timestamp with time zone | | |
Documentation: pg_stat_slru
Change history
- PostgreSQL 13
- added (commit 28cac71b)
Examples
postgres=# SELECT * FROM pg_stat_slru;
name | blks_zeroed | blks_hit | blks_read | blks_written | blks_exists | flushes | truncates | stats_reset
-----------------+-------------+----------+-----------+--------------+-------------+---------+-----------+-------------------------------
CommitTs | 1 | 95 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
MultiXactMember | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
MultiXactOffset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
Notify | 1 | 5 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
Serial | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
Subtrans | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
Xact | 0 | 1131 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
other | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2021-11-03 11:08:05.213091+01
(8 rows)
References
- PostgreSQL documentation: pg_stat_slru
Useful links
- CommitFest entry: SLRU stats