Horton

RE: Temporary tables prevent autovacuum, leading to XID wraparound

Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com>

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From: "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>
To: 'Masahiko Sawada' <sawada.mshk@gmail.com>, Robert Haas <robertmhaas@gmail.com>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-02-02T06:37:46Z
Lists: pgsql-hackers 
From: Masahiko Sawada [mailto:sawada.mshk@gmail.com]
> Thank you for suggestion. It sounds more smarter. So it would be more better
> if we vacuums database for anti-wraparound in ascending order of
> relfrozenxid?

I thought so, too.  The current behavior is inconsistent: the launcher tries to assign all workers to one database with the biggest wraparound risk in order to eliminate the risk as fast as possible, but the workers don't get hurry to reduce the risk.

Regards
Takayuki Tsunakawa

Commits

  1. Clarify comment about assignment and reset of temp namespace ID in MyProc

  2. Make autovacuum more aggressive to remove orphaned temp tables

  3. Don't count background workers against a user's connection limit.