Horton

Re: race condition in pg_class

Michael Paquier <michael@paquier.xyz>

View thread
From: Michael Paquier <michael@paquier.xyz>
To: Noah Misch <noah@leadboat.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Smolkin Grigory <smallkeen@gmail.com>, pgsql-hackers@postgresql.org
Date: 2024-05-13T07:59:59Z
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 Sun, May 12, 2024 at 04:29:23PM -0700, Noah Misch wrote:
> I'm attaching patches implementing the LockTuple() design.  It turns out we
> don't just lose inplace updates.  We also overwrite unrelated tuples,
> reproduced at inplace.spec.  Good starting points are README.tuplock and the
> heap_inplace_update_scan() header comment.

About inplace050-tests-inj-v1.patch.

+	/* Check if blocked_pid is in injection_wait(). */
+	proc = BackendPidGetProc(blocked_pid);
+	if (proc == NULL)
+		PG_RETURN_BOOL(false);	/* session gone: definitely unblocked */
+	wait_event =
+		pgstat_get_wait_event(UINT32_ACCESS_ONCE(proc->wait_event_info));
+	if (wait_event && strncmp("INJECTION_POINT(",
+							  wait_event,
+							  strlen("INJECTION_POINT(")) == 0)
+		PG_RETURN_BOOL(true);

Hmm.  I am not sure that this is the right interface for the job
because this is not only related to injection points but to the
monitoring of a one or more wait events when running a permutation
step.  Perhaps this is something that should be linked to the spec
files with some property area listing the wait events we're expected
to wait on instead when running a step that we know will wait?
--
Michael