Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)
Alexander Lakhin <exclusion@gmail.com>
Attachments
- debug-pg_visibility.patch (text/x-patch) patch
Hello Melanie,
29.01.2026 01:16, Melanie Plageman wrote:
> Thanks for the review!
> I pushed v33 0001-0003 after incorporating your feedback.
The buildfarm animal scorpion has detected an instability of the addition
to pg_visibility from 21796c267 [1]:
80/82 postgresql:pg_visibility-running / pg_visibility-running/regress ERROR 7.23s exit status 1
diff -U3 /home/bf/bf-build/scorpion/HEAD/pgsql/contrib/pg_visibility/expected/pg_visibility.out
/home/bf/bf-build/scorpion/HEAD/pgsql.build/testrun/pg_visibility-running/regress/results/pg_visibility.out
--- /home/bf/bf-build/scorpion/HEAD/pgsql/contrib/pg_visibility/expected/pg_visibility.out 2026-01-26 22:07:12.923378464
+0100
+++ /home/bf/bf-build/scorpion/HEAD/pgsql.build/testrun/pg_visibility-running/regress/results/pg_visibility.out
2026-01-28 20:15:13.802517085 +0100
@@ -213,7 +213,7 @@
select pg_visibility_map_summary('test_vac_unmodified_heap');
pg_visibility_map_summary
---------------------------
- (1,1)
+ (0,0)
(1 row)
-- the checkpoint cleans the buffer dirtied by freezing the sole tuple
@@ -237,7 +237,7 @@
FROM page_header(get_raw_page('test_vac_unmodified_heap', 0));
?column?
----------
- t
+ f
(1 row)
-- vacuum sets the VM
I've managed to reproduce it locally with the attached and:
echo "autovacuum_naptime = 1" > /tmp/temp.config
TEMP_CONFIG=/tmp/temp.config make -s check -C contrib/pg_visibility/
...
ok 85 - pg_visibility 30 ms
not ok 86 - pg_visibility 165 ms
ok 87 - pg_visibility 36 ms
...
# 1 of 100 tests failed.
Could you please look at this?
Probably you'll find [2] helpful.
[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=scorpion&dt=2026-01-28%2019%3A07%3A32
[2] https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=1c64d2fcb
Best regards,
Alexander
Commits
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the thread's linked commits as JSON, with link sources.
API reference →
-
Stabilize btree_gist test against on-access VM setting
- 62407d26b7c9 19 (unreleased) landed
-
Stabilize plancache test against on-access VM setting
- 85ae8ab05334 19 (unreleased) landed
-
Make local buffers pin limit more conservative
- da6874635db2 19 (unreleased) landed
-
Update FSM during prune/freeze replay even if freespace is zero
- b4c1b2be300e 19 (unreleased) landed
-
Pass down information on table modification to scan nodes
- 50eb5faea295 19 (unreleased) landed
-
Thread flags through begin-scan APIs
- dcd8cc1c852c 19 (unreleased) landed
-
Remove PlannedStmt->resultRelations in favor of resultRelationRelids
- 39dcd10a2c49 19 (unreleased) landed
-
Make it cheap to check if a relation is modified by a query
- 0f4c170cf3b8 19 (unreleased) landed
-
Keep newest live XID up-to-date even if page not all-visible
- 9ba3ec076a68 19 (unreleased) landed
-
Add pruning fast path for all-visible and all-frozen pages
- 01b7e4a46d0f 19 (unreleased) landed
-
Detect and fix visibility map corruption in more cases
- 4f7ecca84dda 19 (unreleased) landed
-
Save vmbuffer in heap-specific scan descriptors for on-access pruning
- 99bf1f8aa6cd 19 (unreleased) landed
-
Avoid BufferGetPage() calls in heap_update()
- 8d2c1df4f4c5 19 (unreleased) landed
-
Initialize missing fields in CreateExecutorState()
- a3511443e5e1 19 (unreleased) landed
-
Prefix PruneState->all_{visible,frozen} with set_
- 34cb4254bdb6 19 (unreleased) landed
-
Add PageGetPruneXid() helper
- 68c2dcb9130e 19 (unreleased) landed
-
Move commonly used context into PruneState and simplify helpers
- 59663e4207fd 19 (unreleased) landed
-
Remove table_scan_analyze_next_tuple unneeded parameter OldestXmin
- 284925508ae6 19 (unreleased) landed
-
Simplify visibility check in heap_page_would_be_all_visible()
- 3efe58febc3c 19 (unreleased) landed
-
Rename LVRelState VM-related logging counters
- 5aea60839ba3 19 (unreleased) landed
-
Fix flakiness in the pg_visibility VM-only vacuum test by using a temporary table.
- 4a99ef1a0d11 19 (unreleased) landed
-
Refactor lazy_scan_prune() VM clear logic into helper
- 19af794b660e 19 (unreleased) landed
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Eliminate use of cached VM value in lazy_scan_prune()
- 648a7e28d7c2 19 (unreleased) landed
-
Combine visibilitymap_set() cases in lazy_scan_prune()
- 21796c267d0a 19 (unreleased) landed
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Fix const qualification in prune_freeze_setup()
- 4877391ce894 19 (unreleased) landed
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Simplify vacuum visibility assertion
- bd298f54a0d6 19 (unreleased) landed
-
Split heap_page_prune_and_freeze() into helpers
- e135e044572e 19 (unreleased) landed
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Assert that cutoffs are provided if freezing will be attempted
- cd38b7e77315 19 (unreleased) landed
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Split PruneFreezeParams initializers to one field per line
- 1e14edcea5e1 19 (unreleased) landed
-
Refactor heap_page_prune_and_freeze() parameters into a struct
- 1937ed70621e 19 (unreleased) landed
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Make heap_page_is_all_visible independent of LVRelState
- 3e4705484e0c 19 (unreleased) landed
-
Inline TransactionIdFollows/Precedes[OrEquals]()
- 43b05b38ea4d 19 (unreleased) landed
-
Add helper for freeze determination to heap_page_prune_and_freeze
- c8dd6542bae4 19 (unreleased) landed
-
Bump XLOG_PAGE_MAGIC after xl_heap_prune change
- 4a8fb58671d3 19 (unreleased) landed
-
Correct prune WAL record opcode name in comment
- ae8ea7278c16 19 (unreleased) landed
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Add error codes when vacuum discovers VM corruption
- 8ec97e78a771 19 (unreleased) landed
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Remove unused xl_heap_prune member, reason
- 4b5f206de2bb 19 (unreleased) landed
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Remove unneeded VM pin from VM replay
- 3399c265543e 19 (unreleased) landed
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Add assert and log message to visibilitymap_set
- e3d5ddb7ca91 19 (unreleased) landed
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Stamp HEAD as 19devel.
- 2652835d3efa 19 (unreleased) cited
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Add error codes to some corruption log messages
- fd6ec93bf890 13.0 cited