Re: POC: make mxidoff 64 bits

Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

From: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

To: Maxim Orlov <orlovmg@gmail.com>

Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Alexander Korotkov <aekorotkov@gmail.com>, wenhui qiu <qiuwenhuifx@gmail.com>, Postgres hackers <pgsql-hackers@lists.postgresql.org>

Date: 2025-12-01T12:35:11Z

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 →

Fix partial read handling in pg_upgrade's multixact conversion
- ac94ce8194e5 19 (unreleased) landed
Increase timeout in multixid_conversion upgrade test
- bd43940b02b2 19 (unreleased) landed
Improve sanity checks on multixid members length
- ecb553ae8211 19 (unreleased) landed
Clarify comment on multixid offset wraparound check
- 170361d7b869 14.21 landed
- b0b52b7123ae 15.16 landed
- 7d42e2367c6b 16.12 landed
- cd1a887fe9bf 17.8 landed
- 3fbad030a24d 18.2 landed
- 366dcdaf5779 19 (unreleased) landed
Never store 0 as the nextMXact
- 87a350e1f284 19 (unreleased) landed
Add runtime checks for bogus multixact offsets
- d4b7bde4183b 19 (unreleased) landed
Widen MultiXactOffset to 64 bits
- bd8d9c9bdfa0 19 (unreleased) landed
Move pg_multixact SLRU page format definitions to a separate header
- bb3b1c4f6462 19 (unreleased) landed
Convert confusing macros in multixact.c to static inline functions
- 0099b9408e8c 17.0 landed
Index SLRUs by 64-bit integers rather than by 32-bit integers
- 4ed8f0913bfd 17.0 cited
Cope with possible failure of the oldest MultiXact to exist.
- b6a3444fa635 9.4.4 cited

On Mon, Dec 1, 2025 at 2:23 PM Maxim Orlov <orlovmg@gmail.com> wrote:
>
>
>
> On Fri, 28 Nov 2025 at 16:17, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com> wrote:
>>
>> One more thing,
>> An UPDATE waits for FOR SHARE query to finish, and vice versa. In my
>> experiments I didn't see an UPDATE creating a multi-xact. Why do we
>> have UPDATEs in the load created by the test? Am I missing something?
>
>
> As far as I remember, this was done on purpose to create different
> multixact members statuses randomly.

In that case, better to include that in the comments.

-- 
Best Wishes,
Ashutosh Bapat