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: "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, David Rowley <david.rowley@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-11-15T01:24:50Z
Lists: pgsql-hackers 
On 2018/11/15 10:19, Imai, Yoshikazu wrote:
> On Tue, Nov 13, 2018 at 10:29 PM, Amit Langote wrote:
>> On 2018/11/12 13:35, Imai, Yoshikazu wrote:
>>> How amount of memory is used with above tests is...
>>>
>>> without v5 patches, Set1: 242MB
>>> without v5 patches, Set2: 247MB
>>> with v5 patches, Set1: 420MB
>>> with v5 patches, Set2: 820MB
>>
>> I understood why update/delete planning consumed more memory with the
>> patch.  It was due to a problem with the patch that modifies inheritance
>> update/delete planning.  The exact problem was that the query tree would
>> be translated (hence copied) *twice* for every partition!  First during
>> query planning where the query tree would be translated to figure out
>> a targetlist for partitions and then again before calling
>> grouping_planner.
>> Also, the adjust_appendrel_attrs_multilevel made it worse for
>> multi-level partitioning case, because of repeated copying for root to
>> intermediate partitioned tables, as Imai-san pointed out.
>>
>> I've fixed that making sure that query tree is translated only once and
>> saved for later steps to use.  Imai-san, please check the memory
>> consumption with the latest patch.
> 
> Thanks for fixing!
> Now, memory consumption is lower than the previous.
> 
> with v7 patches, Set1: 223MB
> with v7 patches, Set2: 226MB

Thanks for checking.  So at least we no longer have any memory
over-allocation bug with the patch, but perhaps other bugs are still
lurking. :)

Regards,
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.