Horton

Re: BUG #17255: Server crashes in index_delete_sort_cmp() due to race condition with vacuum

Peter Geoghegan <pg@bowt.ie>

View thread View on postgr.es
From: Peter Geoghegan <pg@bowt.ie>
To: Andres Freund <andres@anarazel.de>
Cc: Dmitry Dolgov <9erthalion6@gmail.com>, Alexander Lakhin <exclusion@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2022-03-11T18:42:30Z
Lists: pgsql-bugs

Attachments

On Thu, Mar 10, 2022 at 7:13 PM Andres Freund <andres@anarazel.de> wrote:
> Large allocation can take a bit. Especially dead_item_alloc() sneakily
> initializes parallelism (which is darn ugly).

Attached v3 revision of the patch makes this a bit clearer.

The patch now moves the pg_class updates for indexes from the end of
lazy_scan_heap() to its heap_vacuum_rel() caller, at the point just
after lazy_scan_heap() returns. This seems logical to me because it
makes all pg_class updates take place inside heap_vacuum_rel(). It
also means that we pretty start parallel mode right at the beginning
of lazy_scan_heap(), and end it right at the end -- which also seems
like a small improvement.

And so we no longer end parallel mode in order to be able to safely
update pg_class for indexes. Rather, we end parallel mode because
processing by lazy_scan_heap() as a whole completed.

-- 
Peter Geoghegan

Commits

  1. vacuumlazy.c: Standardize rel_pages terminology.

  2. vacuumlazy.c: document vistest and OldestXmin.

  3. heap pruning: Only call BufferGetBlockNumber() once.

  4. Fix possible HOT corruption when RECENTLY_DEAD changes to DEAD while pruning.

  5. Assert redirect pointers are sensible after heap_page_prune().

  6. Remove tupgone special case from vacuumlazy.c.

  7. Recycle nbtree pages deleted during same VACUUM.

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

  9. Refactor heap_page_prune so that instead of changing item states on-the-fly,