Horton

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

Michail Nikolaev <michail.nikolaev@gmail.com>

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From: Michail Nikolaev <michail.nikolaev@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Andrey Borodin <amborodin86@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Peter Geoghegan <pg@bowt.ie>, Matthias van de Meent <boekewurm+postgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2023-02-04T12:21:15Z
Lists: pgsql-hackers

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Hello, Andres.

> Not sure I like TransactionIdRetreatSafely() as a name. Maybe
> TransactionIdRetreatClamped() is better?

I think it is better to just replace TransactionIdRetreatedBy.
It is not used anymore after
`v3-0001-WIP-Fix-corruption-due-to-vacuum_defer_cleanup_ag.patch` -
so, it is better to replace the dangerous version in order to avoid
similar issues in the future.
But we need also to move FullXidRelativeTo in that case (not sure it is safe).

> I think it'll make the code easier to read in the other places too, the
> variable names / function names in this space are uncomfortably long to
> fit into 78chars..., particularly when there's two references to the
> same variable in the same line.

Looks fine for my taste, but it is pretty far from perfect :)

Best regards,
Michail.

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.