diff options
| author | Thomas Munro <tmunro@postgresql.org> | 2022-03-16 13:37:58 +1300 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2022-03-16 13:57:07 +1300 |
| commit | 78c0f85e435bf327dcf2c1aded47b51263b32b82 (patch) | |
| tree | 0257c2bb22c24f32aa7f54585725bd66bc0d0637 /doc/src | |
| parent | d9f7ad54e552262ee0090e88d5abd3e04fcdeac8 (diff) | |
Wake up for latches in CheckpointWriteDelay().
The checkpointer shouldn't ignore its latch. Other backends may be
waiting for it to drain the request queue. Hopefully real systems don't
have a full queue often, but the condition is reached easily when
shared_buffers is small.
This involves defining a new wait event, which will appear in the
pg_stat_activity view often due to spread checkpoints.
Back-patch only to 14. Even though the problem exists in earlier
branches too, it's hard to hit there. In 14 we stopped using signal
handlers for latches on Linux, *BSD and macOS, which were previously
hiding this problem by interrupting the sleep (though not reliably, as
the signal could arrive before the sleep begins; precisely the problem
latches address).
Reported-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220226213942.nb7uvb2pamyu26dj%40alap3.anarazel.de
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/monitoring.sgml | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 15e51f92680..b8ffc210a4a 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -2224,6 +2224,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting during base backup when throttling activity.</entry> </row> <row> + <entry><literal>CheckpointerWriteDelay</literal></entry> + <entry>Waiting between writes while performing a checkpoint.</entry> + </row> + <row> <entry><literal>PgSleep</literal></entry> <entry>Waiting due to a call to <function>pg_sleep</function> or a sibling function.</entry> |