Horton

Re: generic plans and "initial" pruning

Chao Li <li.evan.chao@gmail.com>

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From: Chao Li <li.evan.chao@gmail.com>
To: Amit Langote <amitlangote09@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Tender Wang <tndrwang@gmail.com>, Alexander Lakhin <exclusion@gmail.com>, Tomas Vondra <tomas@vondra.me>, Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andres Freund <andres@anarazel.de>, Daniel Gustafsson <daniel@yesql.se>, David Rowley <dgrowleyml@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Thom Brown <thom@linux.com>
Date: 2025-11-24T03:29:53Z
Lists: pgsql-hackers 
Hi, Amit,

Locking only surviving partitions sounds a good optimization. I started to review this patch, but I cannot finish reviewing in one day. I will post my comments as long as I finished some commits.

> On Nov 20, 2025, at 15:30, Amit Langote <amitlangote09@gmail.com> wrote:
> 
> <v3-0004-Use-pruning-aware-locking-in-cached-plans.patch><v3-0005-Add-test-exercising-prep-cleanup-on-cached-plan-i.patch><v3-0002-Introduce-ExecutorPrep-and-refactor-executor-star.patch><v3-0006-Make-SQL-function-executor-track-ExecutorPrep-sta.patch><v3-0003-Reuse-partition-pruning-results-in-parallel-worke.patch><v3-0001-Refactor-partition-pruning-initialization-for-cla.patch>


0001 splits creations of es_part_prune_states into a new function ExecCreatePartitionPruneStates(). With that, you are trying to make the code clearer as you stated in the commit comment. However, the new function is not called, meaning 0001 is not self-contained, feels unusual to me according to the patches I have reviewed so far. I would suggest have ExecDoInitialPruning() call ExecCreatePartitionPruneStates() when es_part_prune_states is still NIL., so that current logic is unchanged, and 0001 can be pushed independently.

0002 moves check permission etc logic from InitPlan() to the new function ExecutorPrep(). The commit message says “executor setup logic unchanged”. Because in old code, before permission check, there was no PushActiveSnapshot(), but in the patch, before check permission, PushActiveSnapshot() is done, which may introduce different behavior, I just wonder why PushActiveSnapshot() is added?

Actually, I am still trying to understand 0002-0004, it would take me some time to fully understand the patch. I’d raise the above comments first. I will continue reviewing this patch tomorrow.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/

Commits

  1. Stamp 19beta1.

  2. Revert "Don't lock partitions pruned by initial pruning"

  3. Ensure first ModifyTable rel initialized if all are pruned

  4. Fix bug in cbc127917 to handle nested Append correctly

  5. Remove unstable test suite added by 525392d57

  6. Don't lock partitions pruned by initial pruning

  7. Fix an oversight in cbc127917 to handle MERGE correctly

  8. Track unpruned relids to avoid processing pruned relations

  9. Perform runtime initial pruning outside ExecInitNode()

  10. Move PartitionPruneInfo out of plan nodes into PlannedStmt

  11. Fix setrefs.c's failure to do expression processing on prune steps.

  12. Remove obsolete executor cleanup code

  13. Revert "Move PartitionPruneInfo out of plan nodes into PlannedStmt"

  14. Move PartitioPruneInfo out of plan nodes into PlannedStmt

  15. Refactor and cleanup runtime partition prune code a little

  16. Remove some unnecessary fields from Plan trees.

  17. Remove more redundant relation locking during executor startup.

  18. Shut down Gather's children before shutting down Gather itself.