Horton

Re: race condition in pg_class

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Noah Misch <noah@leadboat.com>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>, Smolkin Grigory <smallkeen@gmail.com>
Date: 2024-06-12T22:54:07Z
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 Wed, Jun 12, 2024 at 12:32:23PM -0700, Noah Misch wrote:
> On Wed, Jun 12, 2024 at 02:08:31PM -0400, Robert Haas wrote:
>> Personally, I think the fact that injection point wait events were put
>> under Extension is a design mistake that should be corrected before 17
>> is out of beta.

Well, isolation tests and the way to wait for specific points in them
is something I've thought about when working on the initial injpoint
infrastructure, but all my ideas went down to the fact that this is
not specific to injection points: I've also wanted to be able to cause
an isolation to wait for a specific event (class,name).  A hardcoded
sleep is an example.  Even if I discourage anything like that in the
in-core tests because they're slow on fast machines and can be
unreliable on slow machines, it is a fact that they are used by
out-of-core code and that extension developers find them acceptable.

> Works for me.  I don't personally have a problem with the use of Extension,
> since it is a src/test/modules extension creating them.

That's the original reason why Extension has been used in this case,
because the points are assigned in an extension.

> Yes, the last line does refer to that.  Updated table:
> 
> STRATEGY                        | Paquier | Misch | Haas
> --------------------------------------------------------
> new "Injection Point" wait type | maybe   | yes   | yes
> INJECTION_POINT(...) naming     | yes     | yes   | no
> isolation spec says event names | yes     | no    | yes
> 
> I find that's adequate support for the first line.  If there are no objections
> in the next 24hr, I will implement that.

OK.  That sounds like a consensus to me, useful enough for the cases
at hand.
--
Michael