Horton

Re: POC: make mxidoff 64 bits

Maxim Orlov <orlovmg@gmail.com>

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From: Maxim Orlov <orlovmg@gmail.com>
To: wenhui qiu <qiuwenhuifx@gmail.com>
Cc: Alexander Korotkov <aekorotkov@gmail.com>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-09-18T16:37:11Z
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 →

  1. Fix partial read handling in pg_upgrade's multixact conversion

  2. Increase timeout in multixid_conversion upgrade test

  3. Improve sanity checks on multixid members length

  4. Clarify comment on multixid offset wraparound check

  5. Never store 0 as the nextMXact

  6. Add runtime checks for bogus multixact offsets

  7. Widen MultiXactOffset to 64 bits

  8. Move pg_multixact SLRU page format definitions to a separate header

  9. Convert confusing macros in multixact.c to static inline functions

  10. Index SLRUs by 64-bit integers rather than by 32-bit integers

  11. Cope with possible failure of the oldest MultiXact to exist.

Attachments

On Tue, 16 Sept 2025 at 15:12, wenhui qiu <qiuwenhuifx@gmail.com> wrote:

>
> Agree +1 , but I have a question: I remember the XID64 patch got split
> into a few threads. How are these threads related? The original one was
> seen as too big a change, so it was broken up after people raised
> concerns.
>
Yeah, you're absolutely correct. This thread is a part of the overall
work on the transition to XID64 in Postgres. As far as I remember, no
one explicitly raised concerns, but it's clear to me that it won't be
committed as one big patch set.

Here is a WIP patch @ 8191e0c16a for the discussed above issue.
I also had to merge several patches from the previous set, since the
consensus is to use the PRI* format for outputting 64-bit values, and a
separate patch that only changed the format with cast and %llu lost
it's meaning.

If this option suits everyone, the next step is to add a part related
to the pg_upgrade.

-- 
Best regards,
Maxim Orlov.