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Re: pg_plan_advice

Alexander Lakhin <exclusion@gmail.com>

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From: Alexander Lakhin <exclusion@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>, "David G. Johnston" <david.g.johnston@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-03-14T12:00:00Z
Lists: pgsql-hackers 
Hello Robert,

12.03.2026 19:15, Robert Haas wrote:
> I've now committed the main patch. I think that I'm not likely to get
> too much more feedback on that in this release cycle, and I judge that
> more people will be sad if it doesn't get shipped this cycle than if
> it does. That might turn out to be catastrophically wrong, but if many
> problem reports quickly begin to emerge, it can always be reverted.
> I'm hopeful my testing has been thorough enough to avoid that, but
> there's a big difference between lab-testing and real world usage, so
> we'll see.

I've found a crash inside pgpa_join_path_setup(), reproduced with:
echo "geqo_threshold = 2" >/tmp/extra.config
TEMP_CONFIG=/tmp/extra.config make -s check -C contrib/pg_plan_advice/

Program terminated with signal SIGSEGV, Segmentation fault.
(gdb) bt
#0  0x000070820b96d215 in pgpa_join_path_setup (root=0x5ef5a84682b8, joinrel=0x5ef5a8497f10, outerrel=0x5ef5a8472b48,
     innerrel=0x5ef5a84baeb8, jointype=JOIN_UNIQUE_INNER, extra=0x7fff08823490) at pgpa_planner.c:602
#1  0x00005ef57df9742b in add_paths_to_joinrel (root=0x5ef5a84682b8, joinrel=0x5ef5a8497f10, outerrel=0x5ef5a8472b48,
     innerrel=0x5ef5a84baeb8, jointype=JOIN_UNIQUE_INNER, sjinfo=0x5ef5a8473c00, restrictlist=0x5ef5a8498450) at 
joinpath.c:178
#2  0x00005ef57df9d178 in populate_joinrel_with_paths (root=0x5ef5a84682b8, rel1=0x5ef5a8472b48, rel2=0x5ef5a84731f0,
     joinrel=0x5ef5a8497f10, sjinfo=0x5ef5a8473c00, restrictlist=0x5ef5a8498450) at joinrels.c:1197
#3  0x00005ef57df9c6ab in make_join_rel (root=0x5ef5a84682b8, rel1=0x5ef5a8472b48, rel2=0x5ef5a84731f0) at joinrels.c:774
#4  0x00005ef57df700be in merge_clump (root=0x5ef5a84682b8, clumps=0x5ef5a8497e60, new_clump=0x5ef5a8497eb0, num_gene=2,
     force=false) at geqo_eval.c:259
#5  0x00005ef57df6ff3e in gimme_tree (root=0x5ef5a84682b8, tour=0x5ef5a84ba688, num_gene=2) at geqo_eval.c:198
#6  0x00005ef57df6fe12 in geqo_eval (root=0x5ef5a84682b8, tour=0x5ef5a84ba688, num_gene=2) at geqo_eval.c:101
#7  0x00005ef57df708fa in random_init_pool (root=0x5ef5a84682b8, pool=0x5ef5a84c3988) at geqo_pool.c:108
#8  0x00005ef57df70439 in geqo (root=0x5ef5a84682b8, number_of_rels=2, initial_rels=0x5ef5a84ba1f8) at geqo_main.c:127
#9  0x00005ef57df77aa3 in make_rel_from_joinlist (root=0x5ef5a84682b8, joinlist=0x5ef5a8473b40) at allpaths.c:3902
#10 0x00005ef57df715e2 in make_one_rel (root=0x5ef5a84682b8, joinlist=0x5ef5a8473b40) at allpaths.c:240
#11 0x00005ef57dfbede4 in query_planner (root=0x5ef5a84682b8, qp_callback=0x5ef57dfc5ae9 <standard_qp_callback>,
     qp_extra=0x7fff08823af0) at planmain.c:297
...

Could please look at this?

Best regards,
Alexander

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.