Horton

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

Kirill Reshke <reshkekirill@gmail.com>

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From: Kirill Reshke <reshkekirill@gmail.com>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Andrey Borodin <x4mmm@yandex-team.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>
Date: 2025-11-19T09:35:39Z
Lists: pgsql-hackers

Commits

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

  1. Remove table_scan_analyze_next_tuple unneeded parameter OldestXmin

  2. Simplify visibility check in heap_page_would_be_all_visible()

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

  4. Combine visibilitymap_set() cases in lazy_scan_prune()

  5. Fix const qualification in prune_freeze_setup()

  6. Simplify vacuum visibility assertion

  7. Split heap_page_prune_and_freeze() into helpers

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

  9. Split PruneFreezeParams initializers to one field per line

  10. Refactor heap_page_prune_and_freeze() parameters into a struct

  11. Make heap_page_is_all_visible independent of LVRelState

  12. Inline TransactionIdFollows/Precedes[OrEquals]()

  13. Add helper for freeze determination to heap_page_prune_and_freeze

  14. Bump XLOG_PAGE_MAGIC after xl_heap_prune change

  15. Correct prune WAL record opcode name in comment

  16. Add error codes when vacuum discovers VM corruption

  17. Remove unused xl_heap_prune member, reason

  18. Remove unneeded VM pin from VM replay

  19. Add assert and log message to visibilitymap_set

  20. Add error codes to some corruption log messages

On Tue, 18 Nov 2025 at 04:07, Melanie Plageman
<melanieplageman@gmail.com> wrote:
>
> Attached v20 has general cleanup, changes to the table/index AM
> callbacks detailed below, and it moves the
> heap_page_prune_and_freeze() refactoring commit down the stack to
> 0004.
>
> 0001 - 0003 are fairly trivial cleanup patches. I think they are ready
> to commit, so if I don't hear any objections in the next few days,
> I'll go ahead and commit them.
>


Hi! I looked up these 0002-0003 patches once again, LGTM. In
particular, I think 0002 & 0003 makes VM bits management more simple.
My only review comment is about 0003:
Should we make frz_conflict_horizon not a heap_page_will_freeze's
argument but rather just another field of  PruneState struct? If i'm
not mistaken, 'frz_conflict_horizon' fits good to be a part of pruning
state


-- 
Best regards,
Kirill Reshke