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

Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>

From: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: Kirill Reshke <reshkekirill@gmail.com>, 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: 2025-11-20T18:02:20Z
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

Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> writes:

> Melanie Plageman <melanieplageman@gmail.com> writes:
>
>> +			PruneFreezeParams params = {.relation = relation,.buffer = buffer,
>> +				.reason = PRUNE_ON_ACCESS,.options = 0,
>> +				.vistest = vistest,.cutoffs = NULL
>> +			};
>
> I didn't pay much attention to this thread, so I didn't notice this
> until it got committed, but I'd like to lodge an objection to this
> formatting, especially the lack of spaces before the field names. This
> would be much more readable with one struct field per line, i.e.
>
> 	PruneFreezeParams params = {
> 		.relation = rel,
>                 .buffer = buf,
> 		.reason = PRUNE_VACUUM_SCAN,
> 		.options = HEAP_PAGE_PRUNE_FREEZE,
> 		.vistest = vacrel->vistest,
> 		.cutoffs = &vacrel->cutoffs,
> 	};

D'oh, my mail client untabified the .buffer line while I was editing it,
that should of course be:

	PruneFreezeParams params = {
		.relation = rel,
		.buffer = buf,
		.reason = PRUNE_VACUUM_SCAN,
		.options = HEAP_PAGE_PRUNE_FREEZE,
		.vistest = vacrel->vistest,
		.cutoffs = &vacrel->cutoffs,
	};

- ilmari