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Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)

Andrey Borodin <x4mmm@yandex-team.ru>

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From: Andrey Borodin <x4mmm@yandex-team.ru>
To: Kirill Reshke <reshkekirill@gmail.com>
Cc: Melanie Plageman <melanieplageman@gmail.com>, Alexander Lakhin <exclusion@gmail.com>, Andres Freund <andres@anarazel.de>, Chao Li <li.evan.chao@gmail.com>, Xuneng Zhou <xunengzhou@gmail.com>, Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>
Date: 2026-01-30T11:09:34Z
Lists: pgsql-hackers 
Well, converting to TAP seems feasible to me. This will make test more stable.

> On 30 Jan 2026, at 14:59, Kirill Reshke <reshkekirill@gmail.com> wrote:
> 
> I use 'autovacuum-worker-start' injection point to 'disable'
> autovacuum until test is done

If you just set autovacuum off - the test will be executed on bf animals that has no injection points.

Also
x4mmm@x4mmm-osx postgres % git am ~/Downloads/v1-0001-Reimplement-regression-tests-from-21796c267-as-TA.patch 
Applying: Reimplement regression tests from 21796c267 as TAP-test.
.git/rebase-apply/patch:148: trailing whitespace.
# Check that vacuum phase I does not need to modify the heap buffer.  warning: 1 line adds whitespace errors.

There are some typos: "flakky", "introduces", "actuvity", "actaully", "hilding".

Test descriptions are off: you used 'page_header returned as expected' when it's actually about pg_visibility_map_summary.

And, of course, total lack of comments is not good.

However, in principle approach seems good to me.


(FWIW I'm looking into patches 0003-0005 of v33, I'll post when I'll find some nits)


Best regards, Andrey Borodin.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Stabilize btree_gist test against on-access VM setting

  2. Stabilize plancache test against on-access VM setting

  3. Make local buffers pin limit more conservative

  4. Update FSM during prune/freeze replay even if freespace is zero

  5. Pass down information on table modification to scan nodes

  6. Thread flags through begin-scan APIs

  7. Remove PlannedStmt->resultRelations in favor of resultRelationRelids

  8. Make it cheap to check if a relation is modified by a query

  9. Keep newest live XID up-to-date even if page not all-visible

  10. Add pruning fast path for all-visible and all-frozen pages

  11. Detect and fix visibility map corruption in more cases

  12. Save vmbuffer in heap-specific scan descriptors for on-access pruning

  13. Avoid BufferGetPage() calls in heap_update()

  14. Initialize missing fields in CreateExecutorState()

  15. Prefix PruneState->all_{visible,frozen} with set_

  16. Add PageGetPruneXid() helper

  17. Move commonly used context into PruneState and simplify helpers

  18. Remove table_scan_analyze_next_tuple unneeded parameter OldestXmin

  19. Simplify visibility check in heap_page_would_be_all_visible()

  20. Rename LVRelState VM-related logging counters

  21. Fix flakiness in the pg_visibility VM-only vacuum test by using a temporary table.

  22. Refactor lazy_scan_prune() VM clear logic into helper

  23. Eliminate use of cached VM value in lazy_scan_prune()

  24. Combine visibilitymap_set() cases in lazy_scan_prune()

  25. Fix const qualification in prune_freeze_setup()

  26. Simplify vacuum visibility assertion

  27. Split heap_page_prune_and_freeze() into helpers

  28. Assert that cutoffs are provided if freezing will be attempted

  29. Split PruneFreezeParams initializers to one field per line

  30. Refactor heap_page_prune_and_freeze() parameters into a struct

  31. Make heap_page_is_all_visible independent of LVRelState

  32. Inline TransactionIdFollows/Precedes[OrEquals]()

  33. Add helper for freeze determination to heap_page_prune_and_freeze

  34. Bump XLOG_PAGE_MAGIC after xl_heap_prune change

  35. Correct prune WAL record opcode name in comment

  36. Add error codes when vacuum discovers VM corruption

  37. Remove unused xl_heap_prune member, reason

  38. Remove unneeded VM pin from VM replay

  39. Add assert and log message to visibilitymap_set

  40. Stamp HEAD as 19devel.

  41. Add error codes to some corruption log messages