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Re: pg_plan_advice

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Andrei Lepikhov <lepihov@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alexander Lakhin <exclusion@gmail.com>, Lukas Fittl <lukas@fittl.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-04-06T14:01:52Z
Lists: pgsql-hackers 
On Mon, Apr 6, 2026 at 9:22 AM Andrei Lepikhov <lepihov@gmail.com> wrote:
> So, I envision complaints about conflicting extensions in the near
> future - think about Citus or TimescaleDB optimisations, for example.

Definitely possible.

> It would be better to introduce such a code at the beginning of the
> development cycle, not right before the code freeze. At least we would
> discuss its design without rushing.

Yes, the timing is not ideal. However, I posted the patch on October
30th and committed the main patch on March 12th. I think that's a
reasonable length of time to wait for people to provide feedback.
During that time, the only person who provided information on how this
will interact with out-of-core extensions was Lukas Fittl, who came to
the conclusion that the pgs_mask infrastructure will be reusable by
pg_hint_plan and will result in that module being simpler and
involving less code duplication. Other extension authors could have
provided feedback during that time as well, but none did, even after I
posted to my blog to try to raise the visibility of this project. As
far as I can tell, most extension developers don't pay much attention
to core development until after we ship a beta. Had I waited until
July to commit, I think there's a chance that it would have simply
resulted in me getting whatever feedback I'm going to get next summer
rather than this summer. At least this way, the issues will hopefully
be fresh in my mind when the feedback arrives.

Of course, you also seem to be assuming that whatever feedback I get
will be negative, and it may well be. But, there is also some tiny
possibility that I have done a good job and that people will like it.

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Commits

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

  1. pg_plan_advice: Fix another unique-semijoin bug.

  2. pg_plan_advice: Export feedback-related definitions.

  3. pg_plan_advice: Fix a bug when a subquery is pruned away entirely.

  4. pg_plan_advice: Add alternatives test to Makefile.

  5. pg_plan_advice: Handle non-repeatable TABLESAMPLE scans.

  6. pg_stash_advice: Allow stashed advice to be persisted to disk.

  7. Add pg_stash_advice contrib module.

  8. pg_plan_advice: Avoid assertion failure with partitionwise aggregate.

  9. pg_plan_advice: Invent DO_NOT_SCAN(relation_identifier).

  10. Add an alternative_plan_name field to PlannerInfo.

  11. pg_plan_advice: Refactor to invent pgpa_planner_info

  12. Respect disabled_nodes in fix_alternative_subplan.

  13. get_memoize_path: Don't exit quickly when PGS_NESTLOOP_PLAIN is unset.

  14. test_plan_advice: Set TAP test priority 50 in meson.build.

  15. pg_plan_advice: Avoid a crash under GEQO.

  16. Test pg_plan_advice using a new test_plan_advice module.

  17. pg_plan_advice: Always install pg_plan_advice.h, and in the right place

  18. pg_plan_advice: Fix failures to accept identifier keywords.

  19. Add pg_plan_advice contrib module.

  20. Allow extensions to mark an individual index as disabled.

  21. Replace get_relation_info_hook with build_simple_rel_hook.

  22. Store information about Append node consolidation in the final plan.

  23. Store information about elided nodes in the final plan.

  24. Store information about range-table flattening in the final plan.

  25. Pass cursorOptions to planner_setup_hook.

  26. Fix PGS_CONSIDER_NONPARTIAL interaction with Materialize nodes.

  27. Fix mistakes in commit 4020b370f214315b8c10430301898ac21658143f

  28. Allow for plugin control over path generation strategies.

  29. Update some comments for fasthash

  30. Allow passing a pointer to GetNamedDSMSegment()'s init callback.

  31. Don't reset the pathlist of partitioned joinrels.

  32. Treat number of disabled nodes in a path as a separate cost metric.