Horton

Re: speeding up planning with partitions

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: David Rowley <david.rowley@2ndquadrant.com>, Imai Yoshikazu <yoshikazu_i443@live.jp>, "jesper.pedersen@redhat.com" <jesper.pedersen@redhat.com>, "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>, Amit Langote <amitlangote09@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-03-29T18:32:57Z
Lists: pgsql-hackers 
Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> writes:
> On 2019/03/29 7:38, Tom Lane wrote:
>> 2. I seriously dislike what's been done in joinrels.c, too.  That
>> really seems like a kluge (and I haven't had time to study it
>> closely).

> Those hunks account for the fact that pruned partitions, for which we no
> longer create RangeTblEntry and RelOptInfo, may appear on the nullable
> side of an outer join.  We'll need a RelOptInfo holding a dummy path, so
> that outer join paths can be created with one side of join being dummy
> result path, which are built in the patch by  build_dummy_partition_rel().

Just for the record, that code is completely broken: it falls over
badly under GEQO.   (Try running the regression tests with
"alter system set geqo_threshold to 2".)  However, the partitionwise
join code was completely broken for GEQO before this patch, too, so
I'm just going to log that as an open issue for the moment.

			regards, tom lane

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.