Re: Parallel vacuum workers prevent the oldest xmin from advancing

Greg Nancarrow <gregn4422@gmail.com>

From: Greg Nancarrow <gregn4422@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-10-11T06:01:22Z
Lists: pgsql-hackers
On Wed, Oct 6, 2021 at 6:11 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> To fix it, I thought that we change the create index code and the
> vacuum code so that the individual parallel worker sets its status
> flags according to the leader’s one. But ISTM it’d be better to copy
> the leader’s status flags to workers in ParallelWorkerMain(). I've
> attached a patch for HEAD.
>

+1 The fix looks reasonable to me too.
Is it possible for the patch to add test cases for the two identified
problem scenarios? (PROC_IN_VACUUM, PROC_IN_SAFE_IC)

Regards,
Greg Nancarrow
Fujitsu Australia



Commits

  1. Fix parallel operations that prevent oldest xmin from advancing.