Horton

Re: race condition in pg_class

Alexander Lakhin <exclusion@gmail.com>

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From: Alexander Lakhin <exclusion@gmail.com>
To: Noah Misch <noah@leadboat.com>
Cc: pgsql-hackers@postgresql.org
Date: 2024-07-20T08:00:00Z
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.

Hello Noah,

28.06.2024 08:13, Noah Misch wrote:
> Pushed.

A recent buildfarm test failure [1] showed that the
intra-grant-inplace-db.spec test added with 0844b3968 may fail
on a slow machine (per my understanding):

test intra-grant-inplace-db       ... FAILED     4302 ms

@@ -21,8 +21,7 @@
      WHERE datname = current_catalog
          AND age(datfrozenxid) > (SELECT min(age(x)) FROM frozen_witness);

-?column?
-----------------------
-datfrozenxid retreated
-(1 row)
+?column?
+--------
+(0 rows)

whilst the previous (successful) run shows much shorter duration:
test intra-grant-inplace-db       ... ok          540 ms

I reproduced this failure on a VM slowed down so that the test duration
reached 4+ seconds, with 100 test: intra-grant-inplace-db in
isolation_schedule:
test intra-grant-inplace-db       ... ok         4324 ms
test intra-grant-inplace-db       ... FAILED     4633 ms
test intra-grant-inplace-db       ... ok         4649 ms

But as the test going to be modified by the inplace110-successors-v8.patch
and the modified test (with all three latest patches applied) passes
reliably in the same conditions, maybe this failure doesn't deserve a
deeper exploration.

What do you think?

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=habu&dt=2024-07-18%2003%3A08%3A08

Best regards,
Alexander