Horton

Re: New strategies for freezing, advancing relfrozenxid early

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Jeff Davis <pgsql@j-davis.com>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>, John Naylor <john.naylor@enterprisedb.com>, Andres Freund <andres@anarazel.de>, Justin Pryzby <pryzby@telsasoft.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-01-16T18:10:25Z
Lists: pgsql-hackers

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On Sun, Jan 8, 2023 at 5:45 PM Peter Geoghegan <pg@bowt.ie> wrote:
> I didn't have time to incorporate any of the feedback from Matthias
> just yet. That will have to wait until v16.

Attached is v16, which incorporates some of Matthias' feedback.

I've rolled back the major restructuring to the "Routine Vacuuming"
docs that previously appeared in 0003, preferring to take a much more
incremental approach. I do still think that somebody needs to do some
major reworking of that, just in general. That can be done by a
separate patch. There are now only fairly mechanical doc updates in
all 3 patches.

Other changes:

* vacuum_freeze_strategy_threshold is now MB-based, and can be set up to 512TB.

* Various refinements to comments.

--
Peter Geoghegan

Commits

  1. Revert "Add eager and lazy freezing strategies to VACUUM."

  2. Add eager and lazy freezing strategies to VACUUM.

  3. Refine the definition of page-level freezing.

  4. Avoid special XID snapshotConflictHorizon values.

  5. Add page-level freezing to VACUUM.

  6. Remove overzealous MultiXact freeze assertion.

  7. Refactor how VACUUM passes around its XID cutoffs.

  8. Deduplicate freeze plans in freeze WAL records.

  9. Set relfrozenxid to oldest extant XID seen by VACUUM.

  10. Only skip pages marked as clean in the visibility map, if the last 32

  11. Add vacuum_freeze_table_age GUC option, to control when VACUUM should