Horton

Re: Vacuum ERRORs out considering freezing dead tuples from before OldestXmin

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Melanie Plageman <melanieplageman@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Pg Hackers <pgsql-hackers@postgresql.org>, Noah Misch <noah@leadboat.com>
Date: 2024-07-22T18:22:54Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Test that vacuum removes tuples older than OldestXmin

  2. Lower minimum maintenance_work_mem to 64kB

  3. Add accidentally omitted test to meson build file

  4. Use DELETE instead of UPDATE to speed up vacuum test

  5. Revert "Test that vacuum removes tuples older than OldestXmin"

  6. Ensure vacuum removes all visibly dead tuples older than OldestXmin

On Mon, Jul 22, 2024 at 2:13 PM Andres Freund <andres@anarazel.de> wrote:
> It's hard by now (i.e. 17+) because you need substantial amounts of rows to be
> able to trigger it which makes it a hard fight to introduce.

I didn't think that it was particularly hard when I tested the test
that Melanie committed.

> And the cost of
> setting the GUC limit lower is essentially zero.

Apparently you know more about TID Store than me.

If it really is trivial to lower the limit, then I have no objections
to doing so. That would make it easy to fix the test flappiness issues
by just using the much lower limit.

-- 
Peter Geoghegan