I think you are right after reading code in compute_parallel_vacuum_workers() :)
________________________________
发件人: Tom Lane <t...@sss.pgh.pa.us>
发送时间: 2020年12月1日 2:54
收件人: Yulin PEI <ype...@connect.ust.hk>
抄送: Masahiko Sawada <sawada.m...@gmail.com>; pgsql-hackers@lists.postgresql.org
<pgsql-hackers@lists.postgresql.org>
主题: Re: 回复: [PATCH] BUG FIX: Core dump could happen when VACUUM FULL in
standalone mode
Yulin PEI <ype...@connect.ust.hk> writes:
> Yes, I agree because (IsNormalProcessingMode() ) means that current process
> is not in bootstrap mode and postmaster process will not build index.
> So my new modified patch is attached.
This is a good catch, but the proposed fix still seems pretty random
and unlike how it's done elsewhere. It seems to me that since
index_build() is relying on plan_create_index_workers() to assess
parallel safety, that's where to check IsUnderPostmaster. Moreover,
the existing code in compute_parallel_vacuum_workers (which gets
this right) associates the IsUnderPostmaster check with the initial
check on max_parallel_maintenance_workers. So I think that the
right fix is to adopt the compute_parallel_vacuum_workers coding
in plan_create_index_workers, and thereby create a model for future
uses of max_parallel_maintenance_workers to follow.
regards, tom lane
