Re: [HACKERS] Partition-wise aggregation/grouping

From: Jeevan Chalke <jeevan(dot)chalke(at)enterprisedb(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, Rajkumar Raghuwanshi <rajkumar(dot)raghuwanshi(at)enterprisedb(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [HACKERS] Partition-wise aggregation/grouping
Date: 2018-03-23 11:05:59
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On Thu, Mar 22, 2018 at 10:28 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Thu, Mar 22, 2018 at 6:15 AM, Jeevan Chalke
> <jeevan(dot)chalke(at)enterprisedb(dot)com> wrote:
> > Leeks cleaner now. Thanks for refactoring it.
> >
> > I have merged these changes and flatten all previuos changes into the
> main
> > patch.
> Committed 0001-0005.

Thanks Robert.

> I made a few further modifications. These were
> mostly cosmetic, but with two exceptions:
> 1. I moved one set_cheapest() call to avoid doing that twice for the
> top-level grouped_rel.
> 2. I removed the logic to set partition properties for grouped_rels.
> As far as I can see, there's nothing that needs this. It would be
> important if we wanted subsequent planning stages to be able to do
> partition-wise stuff, e.g. when doing window functions or setops, or
> at higher query levels. Maybe we'll have that someday; until then, I
> think this is just a waste of cycles.


Changes related to postgres_fdw which allows pushing aggregate on the
foreign server is not yet committed. Due to this, we will end up getting an
error when we have foreign partitions + aggregation.

Attached 0001 patch here (0006 from my earlier patch-set) which adds
support for this and thus will not have any error.


> --
> Robert Haas
> EnterpriseDB:
> The Enterprise PostgreSQL Company

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

Attachment Content-Type Size
0001-Teach-postgres_fdw-to-push-aggregates-for-child-rela.patch text/x-patch 23.3 KB

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