Horton

Re: BUG #17257: (auto)vacuum hangs within lazy_scan_prune()

Alexander Lakhin <exclusion@gmail.com>

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From: Alexander Lakhin <exclusion@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2024-04-09T20:00:00Z
Lists: pgsql-bugs

Commits

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  1. Ensure vacuum removes all visibly dead tuples older than OldestXmin

  2. Combine freezing and pruning steps in VACUUM

  3. Handle non-chain tuples outside of heap_prune_chain()

  4. Fix false reports in pg_visibility

  5. Remove retry loop in heap_page_prune().

  6. vacuumlazy.c: document vistest and OldestXmin.

  7. Deduplicate choice of horizon for a relation procarray.c.

  8. Remove tupgone special case from vacuumlazy.c.

  9. Simplify state managed by VACUUM.

  10. Recycle nbtree pages deleted during same VACUUM.

  11. snapshot scalability: Don't compute global horizons while building snapshots.

  12. Raise error when affecting tuple moved into different partition.

09.04.2024 21:59, Robert Haas wrote:
>
>> But on dad1539ae I got no failures for 3 runs (the same is on
>> REL_16_STABLE with a slightly modified lazy_scan_prune patch).
> I'm having trouble understanding what this means exactly -- are you
> talking about REL_16_STABLE, or about dad1539ae, or both, or what? At
> any rate, it's really important here that we understand whether we
> still have a bug here, and if so, in which releases and with what test
> case. I wasn't aware of dad1539ae but that certainly seems like it
> might've made a big difference, if not fixing the problem entirely
> then at least making it a lot less likely. And I think it's possible
> that some of the related freezing+pruning commits on master might have
> removed the problem altogether, but that needs to be tested.

I was talking about both — dad1539ae eliminated the bug (judging from the
repro) on REL_14_STABLE, and I suppose that 18b87b201 did the same for
REL_15_STABLE/REL_16_STABLE...
(On 18b87b201~1 I've got (twice):
TRAP: FailedAssertion("HeapTupleHeaderIsHeapOnly(htup)", File: "pruneheap.c", Line: 964, PID: 1854895)

I can double-check exactly 18b87b201 with the repro, if it makes sense.)

Best regards,
Alexander