Re: [HACKERS] Partition-wise aggregation/grouping - Mailing list pgsql-hackers

From Dilip Kumar
Subject Re: [HACKERS] Partition-wise aggregation/grouping
Date
Msg-id CAFiTN-vLMumRVxqmvLEkdyccssmXj1L=dY=_-fvB_1hh1a0yzw@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] Partition-wise aggregation/grouping  (Jeevan Chalke <jeevan.chalke@enterprisedb.com>)
Responses Re: [HACKERS] Partition-wise aggregation/grouping
List pgsql-hackers
On Tue, Oct 17, 2017 at 10:44 PM, Jeevan Chalke
<jeevan.chalke@enterprisedb.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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