Horton

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

Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>

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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: 2025-11-20T17:55:05Z
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

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,
	};

or at a pinch, if we're really being stingy with the vertical space:

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

I had a quick grep, and every other designated struct initialiser I
could find uses the one-field-per-line form, but they're not consistent
about the comma after the last field.  I personally prefer having it, so
that one can add more fields later without having to modify the
unrelated line.

- ilmari