Date: Mon, 27 Jul 2020 14:24:36 -0400
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Jeff Davis <pgsql@j-davis.com>, David Rowley <dgrowleyml@gmail.com>,
	Stephen Frost <sfrost@snowman.net>, Tom Lane <tgl@sss.pgh.pa.us>,
	Andres Freund <andres@anarazel.de>,
	Bruce Momjian <bruce@momjian.us>,
	Robert Haas <robertmhaas@gmail.com>,
	Justin Pryzby <pryzby@telsasoft.com>,
	Melanie Plageman <melanieplageman@gmail.com>,
	Tomas Vondra <tomas.vondra@2ndquadrant.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: Default setting for enable_hashagg_disk
Message-ID: <20200727182436.GA20148@alvherre.pgsql>
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On 2020-Jul-27, Peter Geoghegan wrote:

> On Mon, Jul 27, 2020 at 10:30 AM Alvaro Herrera
> <alvherre@2ndquadrant.com> wrote:
> > On 2020-Jul-23, Peter Geoghegan wrote:
> > I notice you put the prototype for get_hash_mem in nodeHash.h.  This
> > would be fine if not for the fact that optimizer needs to call the
> > function too, which means now optimizer have to include executor headers
> > -- not a great thing.  I'd move the prototype elsewhere to avoid this,
> > and I think miscadmin.h is a decent place for the prototype, next to
> > work_mem and m_w_m.
> 
> The location of get_hash_mem() is awkward,

Yes.

> but there is no obvious alternative.

Agreed.

> Are you proposing that I just put the prototype in miscadmin.h, while
> leaving the implementation where it is (in nodeHash.c)?

Yes, that's in the part of my reply you didn't quote:

: It remains strange to have the function in executor
: implementation, but I don't offhand see a better place, so maybe it's
: okay where it is.

> [...] moving the implementation of get_hash_mem() to either of those
> two files seems worse to me.

Sure.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services