Horton

Re: [CLOBBER_CACHE]Server crashed with segfault 11 while executing clusterdb

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amul Sul <sulamul@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Noah Misch <noah@leadboat.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Neha Sharma <neha.sharma@enterprisedb.com>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2021-03-25T05:50:29Z
Lists: pgsql-hackers 
Amul Sul <sulamul@gmail.com> writes:
> On Wed, Mar 24, 2021 at 8:09 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> static inline struct SMgrRelationData *
>> RelationGetSmgr(Relation rel)
>> {
>>     if (unlikely(rel->rd_smgr == NULL))
>>         RelationOpenSmgr(rel);
>>     return rel->rd_smgr;
>> }

> A quick question: Can't it be a macro instead of an inline function
> like other macros we have in rel.h?

The multiple-evaluation hazard seems like an issue.  We've tolerated
such hazards in the past, but mostly just because we weren't relying
on static inlines being available, so there wasn't a good way around
it.

Also, the conditional evaluation here would look rather ugly
in a macro, I think, if indeed you could do it at all without
provoking compiler warnings.

			regards, tom lane

Commits

  1. Replace RelationOpenSmgr() with RelationGetSmgr().

  2. Avoid possible crash while finishing up a heap rewrite.

  3. Redefine pg_class.reltuples to be -1 before the first VACUUM or ANALYZE.