| From: | Dilip Kumar <dilipbalaut(at)gmail(dot)com> |
|---|---|
| To: | Jeevan Chalke <jeevan(dot)chalke(at)enterprisedb(dot)com> |
| Cc: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>, Rajkumar Raghuwanshi <rajkumar(dot)raghuwanshi(at)enterprisedb(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Partition-wise aggregation/grouping |
| Date: | 2017-10-18 04:23:10 |
| Message-ID: | CAFiTN-vLMumRVxqmvLEkdyccssmXj1L=dY=_-fvB_1hh1a0yzw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Oct 17, 2017 at 10:44 PM, Jeevan Chalke
<jeevan(dot)chalke(at)enterprisedb(dot)com> wrote:
>
> I didn't get what you mean by regression here. Can you please explain?
>
> I see that PWA plan is selected over regular plan when enabled on the basis
> of costing.
> Regular planning need a Result node due to which costing increases where as
> PWA don't need that and thus wins.
Sorry for not clearly explaining, I meant that with normal plan
execution time is 263.678 ms whereas with PWA its 339.929 ms.
I only set enable_partition_wise_agg=on and it switched to PWA and
execution time increased by 30%.
I understand that the this is the worst case for PWA where
FinalizeAggregate is getting all the tuple.
--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com
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