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: Chao Li <li.evan.chao@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Kirill Reshke <reshkekirill@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Andrey Borodin <x4mmm@yandex-team.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>
Date: 2025-12-10T23:35:47Z
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

Attachments

On Tue, Dec 9, 2025 at 12:48 PM Melanie Plageman
<melanieplageman@gmail.com> wrote:
>
> In this set 0001 and 0002 are independent. 0003-0007 are all small
> steps toward the single change in 0007 which combines the VM updates
> into the same WAL record as pruning and freezing. 0008 and 0009 are
> removing the rest of XLOG_HEAP2_VISIBLE. 0010 - 0012 are refactoring
> needed to set the VM during on-access pruning. 0013 - 0015 are small
> steps toward setting the VM on-access. And 0016 sets the prune xid on
> insert so we may set the VM on-access for pages that have only new
> data.

I committed 0001 and 0002. attached v25 reflects that.
0001-0004 refactoring steps for eliminate visible record from phase I
(not probably independent commits in the end)
0005 eliminate XLOG_HEAP2_VISIBLE from phase I vac
0006-0007 removing the rest of XLOG_HEAP2_VISIBLE
0008-0010 refactoring for setting VM on-access
0011-0013 setting the VM on-access
0014 - setting pd_prune_xid on insert

- Melanie