Horton

Re: generic plans and "initial" pruning

Zhihong Yu <zyu@yugabyte.com>

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From: Zhihong Yu <zyu@yugabyte.com>
To: Amit Langote <amitlangote09@gmail.com>
Cc: David Rowley <dgrowleyml@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2022-04-11T03:58:23Z
Lists: pgsql-hackers 
On Sun, Apr 10, 2022 at 8:05 PM Amit Langote <amitlangote09@gmail.com>
wrote:

> On Fri, Apr 8, 2022 at 8:45 PM Amit Langote <amitlangote09@gmail.com>
> wrote:
> > Most looked fine changes to me except a couple of typos, so I've
> > adopted those into the attached new version, even though I know it's
> > too late to try to apply it.
> >
> > + * XXX is it worth doing a bms_copy() on glob->minLockRelids if
> > + * glob->containsInitialPruning is true?. I'm slighly worried that the
> > + * Bitmapset could have a very long empty tail resulting in excessive
> > + * looping during AcquireExecutorLocks().
> > + */
> >
> > I guess I trust your instincts about bitmapset operation efficiency
> > and what you've written here makes sense.  It's typical for leaf
> > partitions to have been appended toward the tail end of rtable and I'd
> > imagine their indexes would be in the tail words of minLockRelids.  If
> > copying the bitmapset removes those useless words, I don't see why we
> > shouldn't do that.  So added:
> >
> > + /*
> > + * It seems worth doing a bms_copy() on glob->minLockRelids if we
> deleted
> > + * bit from it just above to prevent empty tail bits resulting in
> > + * inefficient looping during AcquireExecutorLocks().
> > + */
> > + if (glob->containsInitialPruning)
> > + glob->minLockRelids = bms_copy(glob->minLockRelids)
> >
> > Not 100% about the comment I wrote.
>
> And the quoted code change missed a semicolon in the v14 that I
> hurriedly sent on Friday.   (Had apparently forgotten to `git add` the
> hunk to fix that).
>
> Sending v15 that fixes that to keep the cfbot green for now.
>
> --
> Amit Langote
> EDB: http://www.enterprisedb.com

Hi,

+               /* RT index of the partitione table. */

partitione -> partitioned

Cheers

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.