Horton

Re: BUG: Postgres 14 + vacuum_defer_cleanup_age + FOR UPDATE + UPDATE

Mark Dilger <mark.dilger@enterprisedb.com>

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From: Mark Dilger <mark.dilger@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Andrey Borodin <amborodin86@gmail.com>, Michail Nikolaev <michail.nikolaev@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2023-03-09T20:15:16Z
Lists: pgsql-hackers 

> On Mar 8, 2023, at 4:15 PM, Andres Freund <andres@anarazel.de> wrote:
> 
> I worked some more on the fixes for amcheck, and fixes for amcheck.
> 
> The second amcheck fix ends up correcting some inaccurate output in the tests
> - previously xids from before xid 0 were reported to be in the future.
> 
> Previously there was no test case exercising exceeding nextxid, without
> wrapping around into the past. I added that at the end of
> 004_verify_heapam.pl, because renumbering seemed too annoying.
> 
> What do you think?

The changes look reasonable to me.

> Somewhat random note:
> 
> Is it intentional that we VACUUM FREEZE test ROWCOUNT times? That's
> effectively O(ROWCOUNT^2), albeit with small enough constants to not really
> matter. I don't think we need to insert the rows one-by-one either. Changing
> that to a single INSERT and FREEZE shaves 10-12% off the tests.  I didn't
> change that, but we also fire off a psql for each tuple for heap_page_items(),
> with offset $N no less. That seems to be another 500ms.

I don't recall the reasoning.  Feel free to optimize the tests.

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Fix incorrect TAP test ordering

  2. pg_amcheck: Minor test speedups

  3. amcheck: Fix FullTransactionIdFromXidAndCtx() for xids before epoch 0

  4. amcheck: Fix ordering bug in update_cached_xid_range()

  5. Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids

  6. Add hardening to catch invalid TIDs in indexes.

  7. Use full 64-bit XID for checking if a deleted GiST page is old enough.

  8. Avoid early reuse of btree pages, causing incorrect query results.