Horton

Re: Race conditions in 019_replslot_limit.pl

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

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From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: sawada.mshk@gmail.com
Cc: andres@anarazel.de, hlinnaka@iki.fi, pgsql-hackers@postgresql.org
Date: 2022-02-16T07:12:24Z
Lists: pgsql-hackers 
At Wed, 16 Feb 2022 15:22:27 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in 
> At Wed, 16 Feb 2022 14:58:23 +0900, Masahiko Sawada <sawada.mshk@gmail.com> wrote in 
> > Or it's possible that the process took a time to clean up the
> > temporary replication slot?
> 
> Checkpointer may take ReplicationSlotControlLock. Dead lock between
> ReplicationSlotCleanup and InvalidateObsoleteReplicationSlots
> happened?

Or missing CV broadcast?  Anyway I haven't find a scenario of
interfering between checkpointer and walsender.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

Commits

  1. Revert 019_replslot_limit.pl related debugging aids.

  2. Don't fail for > 1 walsenders in 019_replslot_limit, add debug messages.

  3. Add retries for further investigation of 019_replslot_limit.pl failures.

  4. Add further debug info to help debug 019_replslot_limit.pl failures.

  5. Add temporary debug info to help debug 019_replslot_limit.pl failures.

  6. Move replication slot release to before_shmem_exit().

  7. Server-side fix for delayed NOTIFY and SIGTERM processing.