Horton
Menu

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

David Rowley <dgrowleyml@gmail.com>

View thread
From: David Rowley <dgrowleyml@gmail.com>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: Tomas Vondra <tomas@vondra.me>, Andres Freund <andres@anarazel.de>, Kirill Reshke <reshkekirill@gmail.com>, Chao Li <li.evan.chao@gmail.com>, Andrey Borodin <x4mmm@yandex-team.ru>, Xuneng Zhou <xunengzhou@gmail.com>, Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>
Date: 2026-03-31T02:16:59Z
Lists: pgsql-hackers 
On Mon, 30 Mar 2026 at 06:16, Melanie Plageman
<melanieplageman@gmail.com> wrote:
> Attached v48 does a bit more cleanup. No functional changes. I'm
> planning to push this soon. I think my remaining question is whether I
> should move the row marks and result relation bitmaps into the estate.
> I'm leaning toward not doing that and leaving them in the PlannedStmt.
> Anyway, If I want to replace the list of result relation RTIs in the
> PlannedStmt, I have to leave the bitmapset version there.

I looked at v48-0001 and it looks fine to me. I've only minor quibbles
about you using foreach() instead of foreach_int() and foreach_node()
for populating the new Bitmapsets in standard_planner().

I don't see any advantage to adding the fields to EState. There might
be if there was some performance reason, but it looks like you're only
accessing the fields when scans are initialised. It's hard to imagine
an extra pointer deference would matter there. I didn't find any
guidance in any comments to understand if there's a best practise
here, so I assume what's there today is down to people's taste. For
me, I'd say if it's not performance critical and the executor does not
modify the field for any purpose, then keeping it in PlannedStmt is
fine. If someone thinks I'm wrong on that, then a comment at the top
of EState would be helpful.

David

Commits

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

  1. Stabilize btree_gist test against on-access VM setting

  2. Stabilize plancache test against on-access VM setting

  3. Make local buffers pin limit more conservative

  4. Update FSM during prune/freeze replay even if freespace is zero

  5. Pass down information on table modification to scan nodes

  6. Thread flags through begin-scan APIs

  7. Remove PlannedStmt->resultRelations in favor of resultRelationRelids

  8. Make it cheap to check if a relation is modified by a query

  9. Keep newest live XID up-to-date even if page not all-visible

  10. Add pruning fast path for all-visible and all-frozen pages

  11. Detect and fix visibility map corruption in more cases

  12. Save vmbuffer in heap-specific scan descriptors for on-access pruning

  13. Avoid BufferGetPage() calls in heap_update()

  14. Initialize missing fields in CreateExecutorState()

  15. Prefix PruneState->all_{visible,frozen} with set_

  16. Add PageGetPruneXid() helper

  17. Move commonly used context into PruneState and simplify helpers

  18. Remove table_scan_analyze_next_tuple unneeded parameter OldestXmin

  19. Simplify visibility check in heap_page_would_be_all_visible()

  20. Rename LVRelState VM-related logging counters

  21. Fix flakiness in the pg_visibility VM-only vacuum test by using a temporary table.

  22. Refactor lazy_scan_prune() VM clear logic into helper

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

  24. Combine visibilitymap_set() cases in lazy_scan_prune()

  25. Fix const qualification in prune_freeze_setup()

  26. Simplify vacuum visibility assertion

  27. Split heap_page_prune_and_freeze() into helpers

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

  29. Split PruneFreezeParams initializers to one field per line

  30. Refactor heap_page_prune_and_freeze() parameters into a struct

  31. Make heap_page_is_all_visible independent of LVRelState

  32. Inline TransactionIdFollows/Precedes[OrEquals]()

  33. Add helper for freeze determination to heap_page_prune_and_freeze

  34. Bump XLOG_PAGE_MAGIC after xl_heap_prune change

  35. Correct prune WAL record opcode name in comment

  36. Add error codes when vacuum discovers VM corruption

  37. Remove unused xl_heap_prune member, reason

  38. Remove unneeded VM pin from VM replay

  39. Add assert and log message to visibilitymap_set

  40. Stamp HEAD as 19devel.

  41. Add error codes to some corruption log messages