Horton

RE: speeding up planning with partitions

Imai, Yoshikazu <imai.yoshikazu@jp.fujitsu.com>

View thread View on postgr.es
From: "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>
To: "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>, 'David Rowley' <david.rowley@2ndquadrant.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Amit Langote <amitlangote09@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-11T06:52:11Z
Lists: pgsql-hackers 
On Thu, Jan 10, 2019 at 6:10 PM, Imai, Yoshikazu wrote:
> > Does that not mean that the if (parent->top_parent_relids) will always
> > be false in build_dummy_partition_rel() and it'll only ever get
> > rtekind == RTE_RELATION?
> 
> At least, I checked if (parent->top_parent_relids) can be true if I
> execute below SQL.
> 
> select * from parent p1 inner join parent p2 on p1.a=p2.a where p1.id < 15;

Sorry, I also made mistake. I was executed:
select * from parent p1 inner join parent p2 on p1.a=p2.a where p1.a < 15;

--
Yoshikazu Imai


> -----Original Message-----
> From: Imai, Yoshikazu [mailto:imai.yoshikazu@jp.fujitsu.com]
> Sent: Friday, January 11, 2019 3:10 PM
> To: 'David Rowley' <david.rowley@2ndquadrant.com>; Amit Langote
> <Langote_Amit_f8@lab.ntt.co.jp>
> Cc: Amit Langote <amitlangote09@gmail.com>; Alvaro Herrera
> <alvherre@2ndquadrant.com>; Pg Hackers <pgsql-hackers@postgresql.org>
> Subject: RE: speeding up planning with partitions
> 
> Hi David,
> 
> On Thu, Jan 10, 2019 at 4:02 PM, David Rowley wrote:
> > 3. I wonder if there's a better way to handle what
> > build_dummy_partition_rel() does. I see the child's relid to the
> > parent's relid and makes up a fake AppendRelInfo and puts it in the
> > parent's slot.  What's going to happen when the parent is not the
> > top-level parent? It'll already have a AppendRelInfo set.
> ...
> >
> > select * from parent p1 inner join parent p2 on p1.a=p2.a where p1.id
> > < 10;
> 
> I think there is a mistake in the select SQL.
> "p1.id < 10" doesn't prune any partition because tables are partitioned
> by column "a" in your definition. Isn't it?
> 
> > Does that not mean that the if (parent->top_parent_relids) will always
> > be false in build_dummy_partition_rel() and it'll only ever get
> > rtekind == RTE_RELATION?
> 
> At least, I checked if (parent->top_parent_relids) can be true if I
> execute below SQL.
> 
> select * from parent p1 inner join parent p2 on p1.a=p2.a where p1.id
> < 15;
> 
> I couldn't check other points you mentioned, but I also think
> build_dummy_partition_rel() needs more consideration because I felt it
> has complicated logic when I was checking around here.
> 
> 
> Amit,
> I also realized there are some mistakes in the comments around this
> function.
> 
> + * build_dummy_partition_rel
> + *		Build a RelOptInfo and AppendRelInfo for a pruned
> partition
> s/and AppendRelInfo/and an AppendRelInfo/
> 
> +	 * Now we'll need a (no-op) AppendRelInfo for parent, because
> we're
> +	 * setting the dummy partition's relid to be same as the parent's.
> s/a \(no-op\) AppendRelInfo/an \(no-op\) AppendRelInfo/
> 
> --
> Yoshikazu Imai

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.