Horton

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

Melanie Plageman <melanieplageman@gmail.com>

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From: Melanie Plageman <melanieplageman@gmail.com>
To: Kirill Reshke <reshkekirill@gmail.com>
Cc: Andrey Borodin <x4mmm@yandex-team.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>
Date: 2025-09-05T22:27:05Z
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 Wed, Sep 3, 2025 at 5:06 AM Kirill Reshke <reshkekirill@gmail.com> wrote:
>
> small comments regarding new series
>
> 0001, 0002, 0017 LGTM

Thanks for continuing to review!

> In 0015:
>
> Also, maybe GlobalVisXidTestAllVisible is a slightly better name? (The
> term 'all-visible' is one that we occasionally utilize)

Actually, I was trying to distinguish it from all-visible because I
interpret that to mean every thing is visible -- as in, every tuple on
a page is visible to everyone. And here we are referring to one xid
and want to know if it is visible to everyone as no longer running. I
don't think my name  ("visible-to-all") is good, but I'm hesitant to
co-opt "all-visible" here.

- Melanie