Horton

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

Noah Misch <noah@leadboat.com>

View thread
From: Noah Misch <noah@leadboat.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>, robertmhaas@gmail.com, Alexander Lakhin <exclusion@gmail.com>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>, Andres Freund <andres@anarazel.de>
Date: 2024-01-09T21:44:47Z
Lists: pgsql-bugs

Commits

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

  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.

On Tue, Jan 09, 2024 at 03:59:19PM -0500, Peter Geoghegan wrote:
> On Sat, Jan 6, 2024 at 3:24 PM Noah Misch <noah@leadboat.com> wrote:
> > On Sun, Dec 31, 2023 at 03:53:34PM -0800, Peter Geoghegan wrote:
> > > I am aware of a production database that appears to run into the same
> > > problem. Inserts and concurrent cross-partition updates are used
> > > heavily on this instance (the table in question uses partitioning).
> > > Perhaps you happened upon a similar problematic production database,
> > > and found this thread when researching the issue? Maybe we've both
> > > seen the same problem in the wild?
> >
> > I did find this thread while researching the symptoms I was seeing.  No
> > partitioning where I saw them.
> 
> I'm starting to think that partitioning was just a red herring. The
> instance had problems in the presence of DELETEs, not UPDATEs (or
> cross-partition UPDATEs).
> 
> Did the affected system that you investigated happen to have an
> atypically high number of databases? The system 15.4 system that I saw
> the problem on had almost 3,000 databases.

No, single-digit database count here.