Horton

Re: speeding up planning with partitions

Amit Langote <langote_amit_f8@lab.ntt.co.jp>

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From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: Robert Haas <robertmhaas@gmail.com>
Cc: "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>, Amit Langote <amitlangote09@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, David Rowley <david.rowley@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, "jesper.pedersen@redhat.com" <jesper.pedersen@redhat.com>, Justin Pryzby <pryzby@telsasoft.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-03-20T00:57:40Z
Lists: pgsql-hackers 
On 2019/03/20 9:49, Robert Haas wrote:
> On Fri, Mar 8, 2019 at 4:18 AM Amit Langote
> <Langote_Amit_f8@lab.ntt.co.jp> wrote:
>> Maybe you know that range_table_mutator() spends quite a long time if
>> there are many target children, but I realized there's no need for
>> range_table_mutator() to copy/mutate child target RTEs.  First, there's
>> nothing to translate in their case.  Second, copying them is not necessary
>> too, because they're not modified across different planning cycles.  If we
>> pass to adjust_appendrel_attrs only the RTEs in the original range table
>> (that is, before any child target RTEs were added), then
>> range_table_mutator() has to do significantly less work and allocates lot
>> less memory than before.  I've broken this change into its own patch; see
>> patch 0004.
> 
> Was just glancing over 0001:
> 
> - * every non-join RTE that is used in the query.  Therefore, this routine
> - * is the only place that should call build_simple_rel with reloptkind
> - * RELOPT_BASEREL.  (Note: build_simple_rel recurses internally to build
> - * "other rel" RelOptInfos for the members of any appendrels we find here.)
> + * every non-join RTE that is specified in the query.  Therefore, this
> + * routine is the only place that should call build_simple_rel with
> + * reloptkind RELOPT_BASEREL.  (Note:  "other rel" RelOptInfos for the
> + * members of any appendrels we find here are built later when query_planner
> + * calls add_other_rels_to_query().)
> 
> Used -> specified doesn't seem to change the meaning, so I'm not sure
> what the motivation is there.

Well, I thought it would clarify that now add_base_rels_to_query() only
adds "baserel" RelOptInfos, that is, those for the relations that are
directly mentioned in the query.

Maybe:

...that is mentioned in the query.

or

...that is directly mentioned in the query.

?

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.