Horton

Re: pg_get_wal_replay_pause_state() should not return 'paused' while a promotion is ongoing.

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers@postgresql.org
Date: 2021-05-18T06:46:07Z
Lists: pgsql-hackers 
On Tue, May 18, 2021 at 12:48:38PM +0900, Fujii Masao wrote:
> Currently a promotion causes all available WAL to be replayed before
> a standby becomes a primary whether it was in paused state or not.
> OTOH, something like immediate promotion (i.e., standby becomes
> a primary without replaying outstanding WAL) might be useful for
> some cases. I don't object to that.

Sounds like a "promotion immediate" mode.  It does not sound difficult
nor expensive to add a small test for that in one of the existing
recovery tests triggerring a promotion.  Could you add one based on
pg_get_wal_replay_pause_state()?
--
Michael

Commits

  1. Remove unnecessary use of Time::HiRes from 013_crash_restart.pl.

  2. Add regression test for recovery pause.

  3. Make standby promotion reset the recovery pause state to 'not paused'.

  4. Prefer standby promotion over recovery pause.