Horton

Re: race condition in pg_class

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Heikki Linnakangas <hlinnaka@iki.fi>, Nitin Motiani <nitinmotiani@google.com>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>, Smolkin Grigory <smallkeen@gmail.com>, Michael Paquier <michael@paquier.xyz>, Alexander Lakhin <exclusion@gmail.com>
Date: 2024-09-04T19:57:20Z
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.

Attachments

On Wed, Sep 04, 2024 at 09:00:32PM +0530, Nitin Motiani wrote:
> How about this alternative then? The tuple length check
> and the elog(ERROR) gets its own function. Something like
> heap_inplace_update_validate or
> heap_inplace_update_validate_tuple_length. So in that case, it would
> look like this :
> 
>   genam.c:systable_inplace_update_finish
>     heapam.c:heap_inplace_update_validate/heap_inplace_update_precheck
>     PreInplace_Inval
>     START_CRIT_SECTION
>     heapam.c:heap_inplace_update
>     BUFFER_LOCK_UNLOCK
>     AtInplace_Inval
>     END_CRIT_SECTION
>     UnlockTuple
>     AcceptInvalidationMessages
> 
> This is starting to get complicated though so I don't have any issues
> with just renaming the heap_inplace_update to
> heap_inplace_update_and_unlock.

Complexity aside, I don't see the _precheck design qualifying as a modularity
improvement.

>  Assert(rel->ri_needsLockTagTuple ==  IsInplaceUpdateRelation(rel->relationDesc)
> 
> This can safeguard against users of ResultRelInfo missing this field.

v10 does the rename and adds that assertion.  This question remains open:

On Thu, Aug 22, 2024 at 12:32:00AM -0700, Noah Misch wrote:
> On Tue, Aug 20, 2024 at 11:59:45AM +0300, Heikki Linnakangas wrote:
> > How many of those for RELKIND_INDEX vs tables? I'm thinking if we should
> > always require a tuple lock on indexes, if that would make a difference.
> 
> Three sites.  See attached inplace125 patch.  Is it a net improvement?  If so,
> I'll squash it into inplace120.

If nobody has an opinion, I'll discard inplace125.  I feel it's not a net
improvement, but either way is fine with me.