Horton

Re: speeding up planning with partitions

Amit Langote <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Tom Lane <tgl@sss.pgh.pa.us>, David Rowley <david.rowley@2ndquadrant.com>, "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-02-22T17:54:35Z
Lists: pgsql-hackers

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Hi Justin,

Thanks for checking.

On Sat, Feb 23, 2019 at 1:59 AM Justin Pryzby <pryzby@telsasoft.com> wrote:
>
> On Fri, Feb 22, 2019 at 09:45:38PM +0900, Amit Langote wrote:
> > I have updated the inheritance expansion patch.
> >
> > Patch 0001 rewrites optimizer/utils/inherit.c, so that it allows
>
> Thanks for your continued work on this.
>
> I applied v23 patch and imported one of our customers' schema, and ran explain
> on a table with 210 partitions.  With patch applied there are 10x fewer system
> calls, as intended.
>
> with patch:
>     173 pread64
>      76 lseek
>      47 open
>      38 brk
>
> without patch:
>    1276 lseek
>     693 pread64
>     647 open
>     594 brk

OK, great.  I guess you were running SELECT?  Just in case you missed,
the patch to improve UPDATE/DELETE scalability is no longer part of
this patch series.

> > +             if (IS_SIMPLE_REL(rel1) && child_rel1 == NULL)
> > +                     child_rel1 = build_dummy_partition_rel(root, rel1, baserel1,
> > +                                                                                                cnt_parts);
> > +             if (IS_SIMPLE_REL(rel1) && child_rel2 == NULL)
> > +                     child_rel2 = build_dummy_partition_rel(root, rel2, baserel2,
> > +                                                                                                cnt_parts);
>
> Should 2nd "if" say IS_SIMPLE_REL(rel2) ?

Good catch, fixed.  Apparently not guarded by a test, but I haven't
bothered to add new tests with this patch series.

Please find attached updated patches.  I've made a few updates in last
couple of hours such as improving comments, fixing a few thinkos in
inheritance_planner changes, etc.

Thanks,
Amit

Commits

  1. Clean up handling of constraint_exclusion and enable_partition_pruning.

  2. Add test case exercising formerly-unreached code in inheritance_planner.

  3. Speed up planning when partitions can be pruned at plan time.

  4. Avoid crash in partitionwise join planning under GEQO.

  5. Avoid passing query tlist around separately from root->processed_tlist.

  6. Build "other rels" of appendrel baserels in a separate step.

  7. Get rid of duplicate child RTE for a partitioned table.

  8. Rearrange make_partitionedrel_pruneinfo to avoid work when we can't prune.

  9. Don't copy PartitionBoundInfo in set_relation_partition_info.

  10. Move building of child base quals out into a new function

  11. Reorganize planner code moved in b60c39759908

  12. Move inheritance expansion code into its own file

  13. Fix inherited UPDATE/DELETE with UNION ALL subqueries.

  14. Rearrange planner to save the whole PlannerInfo (subroot) for a subquery.