Re: New strategies for freezing, advancing relfrozenxid early

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>

To: Justin Pryzby <pryzby@telsasoft.com>

Cc: Jeff Davis <pgsql@j-davis.com>, pgsql-hackers@lists.postgresql.org

Date: 2022-11-16T03:02:12Z

Lists: pgsql-hackers

Attachments

v6-0005-Avoid-allocating-MultiXacts-during-VACUUM.patch (application/x-patch) patch v6-0005
v6-0004-Make-VACUUM-s-aggressive-behaviors-continuous.patch (application/x-patch) patch v6-0004
v6-0001-Add-page-level-freezing-to-VACUUM.patch (application/x-patch) patch v6-0001
v6-0003-Add-eager-freezing-strategy-to-VACUUM.patch (application/x-patch) patch v6-0003
v6-0002-Teach-VACUUM-to-use-visibility-map-snapshot.patch (application/x-patch) patch v6-0002
v6-0006-Size-VACUUM-s-dead_items-space-using-VM-snapshot.patch (application/x-patch) patch v6-0006

On Thu, Nov 10, 2022 at 7:44 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
> performing post-bootstrap initialization ...
> ../src/backend/access/heap/visibilitymap.c:482:38: runtime error: load of misaligned address 0x5559e1352424 for type 'uint64', which requires 8 byte alignment

This issue is fixed in the attached revision, v6. I now avoid breaking
alignment-picky platforms in visibilitymap.c by using PGAlignedBlock
in the vm snapshot struct (this replaces the raw char buffer used in
earlier revisions).

Posting v6 will also keep CFTester happy. v5 no longer applies cleanly
due to conflicts caused by today's "Deduplicate freeze plans in freeze
WAL records" commit.

No other changes in v6 that are worth noting here.

Thanks
--
Peter Geoghegan

Commits

Revert "Add eager and lazy freezing strategies to VACUUM."
- 6c6b49726644 16.0 landed
Add eager and lazy freezing strategies to VACUUM.
- 4d4179926139 16.0 landed
Refine the definition of page-level freezing.
- b37a08323964 16.0 landed
Avoid special XID snapshotConflictHorizon values.
- 6daeeb1f9196 16.0 cited
Add page-level freezing to VACUUM.
- 1de58df4fec7 16.0 landed
Remove overzealous MultiXact freeze assertion.
- 63c844a0a5d7 16.0 landed
Refactor how VACUUM passes around its XID cutoffs.
- 4ce3afb82ecf 16.0 landed
Deduplicate freeze plans in freeze WAL records.
- 9e5405993c1e 16.0 cited
Set relfrozenxid to oldest extant XID seen by VACUUM.
- 0b018fabaaba 15.0 cited
Only skip pages marked as clean in the visibility map, if the last 32
- bf136cf6e376 8.4.0 cited
Add vacuum_freeze_table_age GUC option, to control when VACUUM should
- 6587818542e7 8.4.0 cited