Date: Fri, 7 Apr 2023 22:53:53 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: "Fujii.Yuki@df.MitsubishiElectric.co.jp" <Fujii.Yuki@df.mitsubishielectric.co.jp>,
	Andres Freund <andres@anarazel.de>,
	Alexander Pyhalov <a.pyhalov@postgrespro.ru>,
	Tomas Vondra <tomas.vondra@enterprisedb.com>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>,
	Julien Rouhaud <rjuju123@gmail.com>,
	Daniel Gustafsson <daniel@yesql.se>,
	Ilya Gladyshev <i.gladyshev@postgrespro.ru>
Subject: Re: Partial aggregates pushdown
Message-ID: <ZDDXQbPxdNU63i0S@momjian.us>
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On Fri, Apr  7, 2023 at 10:44:09PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > On Fri, Apr  7, 2023 at 09:55:00PM -0400, Tom Lane wrote:
> >> Uh, what?  Why would we not be able to tell from the remote server's
> >> version number whether it has this ability?
> 
> > The issue is not a mismatch of postgres_fdw versions but the extension
> > versions and whether the partial aggregate functions exist on the remote
> > side, e.g., something like a PostGIS upgrade.
> 
> postgres_fdw has no business pushing down calls to non-builtin functions
> unless the user has explicitly authorized that via the existing
> whitelisting mechanism.  I think you're reinventing the wheel,
> and not very well.

The patch has you assign an option at CREATE AGGREGATE time if it can do
push down, and postgres_fdw checks that.  What whitelisting mechanism
are you talking about?  async_capable?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Embrace your flaws.  They make you human, rather than perfect,
  which you will never be.