Horton

Re: Extended Statistics set/restore/clear functions.

Corey Huinker <corey.huinker@gmail.com>

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From: Corey Huinker <corey.huinker@gmail.com>
To: jian he <jian.universality@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Tomas Vondra <tomas@vondra.me>, pgsql-hackers@lists.postgresql.org, tgl@sss.pgh.pa.us
Date: 2025-11-13T07:32:17Z
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. Add test doing some cloning of extended statistics data

  2. Add test for pg_restore_extended_stats() with multiranges

  3. Add support for "mcv" in pg_restore_extended_stats()

  4. Include extended statistics data in pg_dump

  5. Add support for "dependencies" in pg_restore_extended_stats()

  6. Add test for MAINTAIN permission with pg_restore_extended_stats()

  7. Add pg_restore_extended_stats()

  8. Add routine to free MCVList

  9. Improve pg_clear_extended_stats() with incorrect relation/stats combination

  10. Add pg_clear_extended_stats()

  11. Introduce routines to validate and free MVNDistinct and MVDependencies

  12. Fix typo in stat_utils.c

  13. Move attribute statistics functions to stat_utils.c

  14. Improve error messages of input functions for pg_dependencies and pg_ndistinct

  15. Improve test output of extended statistics for ndistinct and dependencies

  16. Fix some compiler warnings

  17. Add input function for data type pg_dependencies

  18. Add input function for data type pg_ndistinct

  19. Rework output format of pg_dependencies

  20. Rework output format of pg_ndistinct

  21. Fix comments of output routines for pg_ndistinct and pg_dependencies

  22. Move code specific to pg_dependencies to new file

  23. Move code specific to pg_ndistinct to new file

  24. Document some structures in attribute_stats.c

  25. Fix FATAL message for invalid recovery timeline at beginning of recovery

On Thu, Nov 13, 2025 at 2:02 AM jian he <jian.universality@gmail.com> wrote:

> hi.
>
> v12-0001 and v12-0002 overall look good to me.
>
>         if (dependency->nattributes <= 1)
>             elog(ERROR, "invalid zero-length nattributes array in
> MVDependencies");
> This is an unlikely-to-happen error message,  but still, “nattributes”
> seems confusing?
>

Agreed the error message should be changed if it's kept at all. That error
may never occur now that we test for empty arrays in the array close event
handler. So maybe this becomes a plain assert().


> similarly, in doc/src/sgml/perform.sgml, I think the query should be:
>
> SELECT stxkeys AS k, jsonb_pretty(stxdndistinct::text::jsonb) AS nd
>   FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid)
>   WHERE stxname = 'stts2'    \gx
>

The example almost certainly predates \gx, so that's a good suggestion.