Horton
Menu

Re: Fix bug in multixact Oldest*MXactId initialization and access

Yura Sokolov <y.sokolov@postgrespro.ru>

View thread
From: Yura Sokolov <y.sokolov@postgrespro.ru>
To: Sami Imseih <samimseih@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Chao Li <li.evan.chao@gmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2026-03-03T12:02:06Z
Lists: pgsql-hackers 
02.03.2026 22:09, Sami Imseih пишет:
>>> It says “Each is indexed by ProcNumber”, but it’s no longer accurate for OldestMemberMXactId prepared-xact entries, which now use index (procno - FIRST_PREPARED_XACT_PROC_NUMBER).
>>
>> Fixed those and some other comment work, and pushed. Thanks!
>>
> 
> Thanks! what are your thoughts about adding a test like the one
> here [1] ? This allows us to test correct handling of prepared
> transaction dummy procs. The asserts added will not cover
> this case.
> 
> What do you think?
> 
> [1] [https://www.postgresql.org/message-id/CAA5RZ0twq5bNMq0r0QNoopQnAEv%2BJ3qJNCrLs7HVqTEntBhJ%3Dg%40mail.gmail.com]
I support: test for bug fixed is a good thing.

-- 
regards
Yura Sokolov aka funny-falcon

Commits

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

  1. Add test for row-locking and multixids with prepared transactions

  2. Skip prepared_xacts test if max_prepared_transactions < 2

  3. Fix OldestMemberMXactId and OldestVisibleMXactId array usage

  4. Redefine backend ID to be an index into the proc array

  5. Fix an old bug in multixact and two-phase commit. Prepared transactions can