Horton

Re: generic plans and "initial" pruning

Amit Langote <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Andres Freund <andres@anarazel.de>, Daniel Gustafsson <daniel@yesql.se>, David Rowley <dgrowleyml@gmail.com>, Jacob Champion <jchampion@timescale.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Thom Brown <thom@linux.com>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2023-09-06T09:12:28Z
Lists: pgsql-hackers

Attachments

On Tue, Sep 5, 2023 at 11:41 PM Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, Sep 5, 2023 at 3:13 AM Amit Langote <amitlangote09@gmail.com> wrote:
> > Attached 0001 removes unnecessary cleanup calls from ExecEnd*() routines.
>
> It also adds a few random Assert()s to verify that unrelated pointers
> are not NULL. I suggest that it shouldn't do that.

OK, removed.

> The commit message doesn't mention the removal of the calls to
> ExecDropSingleTupleTableSlot. It's not clear to me why that's OK and I
> think it would be nice to mention it in the commit message, assuming
> that it is in fact OK.

That is not OK, so I dropped their removal. I think I confused them
with slots in other functions initialized with
ExecInitExtraTupleSlot() that *are* put into the estate.

> I suggest changing the subject line of the commit to something like
> "Remove obsolete executor cleanup code."

Sure.

> > 0002 adds NULLness checks in ExecEnd*() routines on some pointers that
> > may not be initialized by the corresponding ExecInit*() routines in
> > the case where it returns early.
>
> I think you should only add these where it's needed. For example, I
> think list_free_deep(NIL) is fine.

OK, done.

> The changes to ExecEndForeignScan look like they include stuff that
> belongs in 0001.

Oops, yes.  Moved to 0001.

> Personally, I prefer explicit NULL-tests i.e. if (x != NULL) to
> implicit ones like if (x), but opinions vary.

I agree, so changed all the new tests to use (x != NULL) form.
Typically, I try to stick with whatever style is used in the nearby
code, though I can see both styles being used in the ExecEnd*()
routines.  I opted to use the style that we both happen to prefer.

Attached updated patches.  Thanks for the review.


--
Thanks, Amit Langote
EDB: http://www.enterprisedb.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.