Horton

Re: race condition in pg_class

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Smolkin Grigory <smallkeen@gmail.com>, pgsql-hackers@postgresql.org
Date: 2024-05-13T20:30:38Z
Lists: pgsql-hackers

Commits

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

  1. Replace tests of ALTER DATABASE RESET TABLESPACE.

  2. meson: Flush stdout in testwrap

  3. Fix catcache invalidation of a list entry that's being built

  4. Stop reading uninitialized memory in heap_inplace_lock().

  5. Fix use of uninitialized value in previous commit.

  6. Back-patch "Refactor code in tablecmds.c to check and process tablespace moves"

  7. Fix data loss at inplace update after heap_update().

  8. For inplace update durability, make heap_update() callers wait.

  9. Warn if LOCKTAG_TUPLE is held at commit, under debug_assertions.

  10. Don't lose partitioned table reltuples=0 after relhassubclass=f.

  11. Fix new assertion for MERGE view_name ... DO NOTHING.

  12. Remove configuration-dependent output from new inplace-inval test.

  13. AccessExclusiveLock new relations just after assigning the OID.

  14. Cope with inplace update making catcache stale during TOAST fetch.

  15. Expand comments and add an assertion in nodeModifyTable.c.

  16. Improve test coverage for changes to inplace-updated catalogs.

  17. Lock before setting relhassubclass on RELKIND_PARTITIONED_INDEX.

  18. Lock owned sequences during ALTER TABLE SET { LOGGED | UNLOGGED }.

  19. Make TAP todo_start effects the same under Meson and prove_check.

  20. Add an injection_points isolation test suite.

  21. Add wait event type "InjectionPoint", a custom type like "Extension".

  22. Create waitfuncs.c for pg_isolation_test_session_is_blocked().

  23. Rework planning and execution of UPDATE and DELETE.

On Mon, May 13, 2024 at 03:53:08PM -0400, Robert Haas wrote:
> On Sun, May 12, 2024 at 7:29 PM Noah Misch <noah@leadboat.com> wrote:
> > - [consequences limited to transient failure] Since a PROC_IN_VACUUM backend's
> >   xmin does not stop pruning, an MVCC scan in that backend can find zero
> >   tuples when one is live.  This is like what all backends got in the days of
> >   SnapshotNow catalog scans.  See the pgbench test suite addition.  (Perhaps
> >   the fix is to make VACUUM do its MVCC scans outside of PROC_IN_VACUUM,
> >   setting that flag later and unsetting it earlier.)
> 
> Are you saying that this is a problem already, or that the patch
> causes it to start happening? If it's the former, that's horrible.

The former.