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

From Jeevan Chalke
Subject Re: [HACKERS] Partition-wise aggregation/grouping
Date
Msg-id CAM2+6=VqUA7LeFpb+Pd3AtFDs=H2O+KXCiq_w+RwCTpHZdzRNw@mail.gmail.com
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In response to Re: [HACKERS] Partition-wise aggregation/grouping  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: [HACKERS] Partition-wise aggregation/grouping  (Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>)
List pgsql-hackers


On Thu, Mar 8, 2018 at 7:49 PM, Robert Haas <robertmhaas@gmail.com> wrote:
On Thu, Mar 8, 2018 at 9:15 AM, Jeevan Chalke
<jeevan.chalke@enterprisedb.com> wrote:
> I am not sure why we don't set reltarget into the grouped_rel too.
>
> But if we do so like we did in partially_grouped_rel, then it will be lot
> easier for partitionwise aggregate as then we don't have to pass target to
> functions creating paths like create_append_path. We now need to update
> generate_gather_paths() to take target too as it is now being called on
> grouped_rel in which reltarget is not set.
>
> But yes, if there is any specific reason we can't do so, then I think the
> same like Ashutosh Said. I didn't aware of such reason though.

I see no problem with setting reltarget for the grouped_rel.  Before
we added partially_grouped_rel, that rel computed paths with two
different targets: partial paths had the partial grouping target, and
non-partial paths had the ordinary grouping target.  But that's fixed
now.

OK.
Will update my changes accordingly.
If we set reltarget into the grouped_rel now, then I don't need one of the refactoring patch which is passing target to the path creation functions.


--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



--
Jeevan Chalke
Technical Architect, Product Development
EnterpriseDB Corporation
The Enterprise PostgreSQL Company

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