Horton

Re: New strategies for freezing, advancing relfrozenxid early

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-10-04T17:39:31Z
Lists: pgsql-hackers 
On Mon, 2022-10-03 at 22:45 -0700, Peter Geoghegan wrote:
> Once a table becomes larger than vacuum_freeze_strategy_threshold,
> VACUUM stops marking pages all-visible in the first place,
> consistently marking them all-frozen instead.

What are the trade-offs here? Why does it depend on table size?

Regards,
	Jeff Davis

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