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

Melanie Plageman <melanieplageman@gmail.com>

From: Melanie Plageman <melanieplageman@gmail.com>

To: Masahiko Sawada <sawada.mshk@gmail.com>

Cc: Tom Lane <tgl@sss.pgh.pa.us>, Peter Geoghegan <pg@bowt.ie>, Heikki Linnakangas <hlinnaka@iki.fi>, Pg Hackers <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Noah Misch <noah@leadboat.com>

Date: 2024-07-22T21:04:34Z

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 →

Test that vacuum removes tuples older than OldestXmin
- 2c0bc4765741 17.6 landed
- 303ba0573ce6 18.0 landed
- 80c34692e8e6 17.0 landed
- aa607980aee0 18.0 landed
Lower minimum maintenance_work_mem to 64kB
- 2eda3df9ad53 17.0 landed
- bbf668d66fbf 18.0 landed
Add accidentally omitted test to meson build file
- 9d198f4d3e3b 16.4 landed
Use DELETE instead of UPDATE to speed up vacuum test
- 924a08b76f5d 14.13 landed
- 9744fe24118b 15.8 landed
- 571e0ee40ebd 16.4 landed
Revert "Test that vacuum removes tuples older than OldestXmin"
- efcbb76efe40 18.0 landed
- 1a3e90948b50 17.0 landed
Ensure vacuum removes all visibly dead tuples older than OldestXmin
- fd4f12df5e46 17.0 landed
- 83c39a1f7f3f 18.0 landed

On Mon, Jul 22, 2024 at 2:17 PM Melanie Plageman
<melanieplageman@gmail.com> wrote:
>
> So, I've just gone through all the test failures on master and 17 for
> mamba, gull, mereswine, and copperhead. I wanted to confirm that the
> test was always failing for the same reason and also if it had any
> failures pre-TIDStore.
>
> We've only run tests with this commit on some of the back branches for
> some of these animals. Of those, I don't see any failures so far. So,
> it seems the test instability is just related to trying to get
> multiple passes of index vacuuming reliably with TIDStore.
>
> AFAICT, all the 32bit machine failures are timeouts waiting for the
> standby to catch up (mamba, gull, merswine). Unfortunately, the
> failures on copperhead (a 64 bit machine) are because we don't
> actually succeed in triggering a second vacuum pass. This would not be
> fixed by a longer timeout.
>
> Because of this, I'm inclined to revert the test on 17 and master to
> avoid distracting folks committing other work and seeing those animals
> go red.

Okay, I reverted this for now on 17 and master. Adding Sawada-san to
the thread to see if he has any ideas for a smaller two-round index
vacuum example.

- Melanie