Horton

Re: PANIC: wrong buffer passed to visibilitymap_clear

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-04-11T16:10:42Z
Lists: pgsql-hackers 
On Sun, Apr 11, 2021 at 8:57 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Does this patch seem to fix the problem?
>
> Hmm ... that looks pretty suspicious, I agree, but why wouldn't an
> exclusive buffer lock be enough to prevent concurrency with heap_update?

I don't have any reason to believe that using a super-exclusive lock
during heap page vacuuming is necessary. My guess is that returning to
doing it that way might make the buildfarm green again. That would at
least confirm my suspicion that this code is relevant. The
super-exclusive lock might have been masking the problem for a long
time.

How about temporarily committing this patch, just to review how it
affects the buildfarm?

-- 
Peter Geoghegan

Commits

  1. Avoid improbable PANIC during heap_update.

  2. Refactor lazy_scan_heap() loop.