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: 2025-10-27T15:54:35Z
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

Here is a new patch set @ 10b5bb3bffaee8

As previously stated, the patch set implements the concept of saving the
"difference" between page offsets in order to save disc space.

The second significant change was that I decided to modify the
pg_upgrade portion as suggested by Heikki above.

At the very least, the logic becomes much simpler and completely
replicates what is done in the multxact.c module and provide some
optimization.

Perhaps this will be easier to comprehend and analyse than attempting
to correctly convert bytes from one format to another.

In the near future, I intend to focus on testing and implement a test
suite.

-- 
Best regards,
Maxim Orlov.