Use WaitLatch() instead of pg_usleep() at end-of-vacuum truncation

This has the advantage to make a process more responsive when the
postmaster dies, even if the wait time was rather limited as there was
only a 50ms timeout here.  Another advantage of this change is for
monitoring, as we gain a new wait event for the end-of-vacuum
truncation.

Author: Bharath Rupireddy
Reviewed-by: Aleksander Alekseev, Thomas Munro, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACU4AdPCq6NLfcA-ZGwX7pPCK5FgEj-CAU0xCKzkASSy_A@mail.gmail.com
This commit is contained in:
Michael Paquier 2021-07-02 12:58:34 +09:00
parent a2595e039c
commit 70685385d7
4 changed files with 15 additions and 2 deletions

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@ -2242,6 +2242,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
<entry><literal>VacuumDelay</literal></entry>
<entry>Waiting in a cost-based vacuum delay point.</entry>
</row>
<row>
<entry><literal>VacuumTruncate</literal></entry>
<entry>Waiting to acquire an exclusive lock to truncate off any
empty pages at the end of a table vacuumed.</entry>
</row>
</tbody>
</tgroup>
</table>

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@ -3236,7 +3236,11 @@ lazy_truncate_heap(LVRelState *vacrel)
return;
}
pg_usleep(VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL * 1000L);
(void) WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL,
WAIT_EVENT_VACUUM_TRUNCATE);
ResetLatch(MyLatch);
}
/*

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@ -485,6 +485,9 @@ pgstat_get_wait_timeout(WaitEventTimeout w)
case WAIT_EVENT_VACUUM_DELAY:
event_name = "VacuumDelay";
break;
case WAIT_EVENT_VACUUM_TRUNCATE:
event_name = "VacuumTruncate";
break;
/* no default case, so that compiler will warn */
}

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@ -140,7 +140,8 @@ typedef enum
WAIT_EVENT_PG_SLEEP,
WAIT_EVENT_RECOVERY_APPLY_DELAY,
WAIT_EVENT_RECOVERY_RETRIEVE_RETRY_INTERVAL,
WAIT_EVENT_VACUUM_DELAY
WAIT_EVENT_VACUUM_DELAY,
WAIT_EVENT_VACUUM_TRUNCATE
} WaitEventTimeout;
/* ----------