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: David Rowley <david.rowley@2ndquadrant.com>
Cc: "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-28T08:21:01Z
Lists: pgsql-hackers 
Hi David,

On 2019/01/28 13:18, David Rowley wrote:
> On Sat, 12 Jan 2019 at 02:00, Amit Langote wrote:
>> On 2019/01/09 9:09, David Rowley wrote:
>>> postgres=# update parent set c = c where a = 333;
>>> server closed the connection unexpectedly
>>>         This probably means the server terminated abnormally
>>>         before or while processing the request.
>>>
>>> I didn't look into what's causing the crash.
>>
>> I tried your example, but it didn't crash for me:
>>
>> explain update parent set c = c where a = 333;
>>                      QUERY PLAN
>> ────────────────────────────────────────────────────
>>  Update on parent  (cost=0.00..0.00 rows=0 width=0)
>>    ->  Result  (cost=0.00..0.00 rows=0 width=54)
>>          One-Time Filter: false
>> (3 rows)
> 
> I had a closer look. The crash is due to
> set_inherit_target_rel_sizes() forgetting to set has_live_children to
> false. This results in the relation not properly being set to a dummy
> rel and the code then making a modify table node without any subnodes.
> That crashes due to getTargetResultRelInfo() returning NULL due to
> rootResultRelInfo and resultRelInfo both being NULL.

Oops, you're right.

> The attached fixes it. If you were not seeing the crash then
> has_live_children must have been zero/false by chance during your
> test.

Thanks for the fix, I'll incorporate it in the next version I'll post by
tomorrow.

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.