From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@bowt.ie>
cc: Robert Haas <robertmhaas@gmail.com>,
        Peter Eisentraut <peter.eisentraut@2ndquadrant.com>,
        pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Remove configure --disable-float4-byval and
 --disable-float8-byval
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Comments: In-reply-to Peter Geoghegan <pg@bowt.ie>
	message dated "Fri, 01 Nov 2019 08:22:27 -0700"
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Date: Fri, 01 Nov 2019 14:00:10 -0400
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Peter Geoghegan <pg@bowt.ie> writes:
> On Fri, Nov 1, 2019 at 7:41 AM Robert Haas <robertmhaas@gmail.com> wrote:
>> Could we get around this by making Datum 8 bytes everywhere?

> I really like that idea.

> Even Raspberry Pi devices (which can cost as little as $35) use 64-bit
> ARM processors. It's abundantly clear that 32-bit platforms do not
> matter enough to justify keeping all the SIZEOF_DATUM crud around.

This line of argument seems to me to be the moral equivalent of
"let's drop 32-bit support altogether".  I'm not entirely on board
with that.  Certainly, a lot of the world is 64-bit these days,
but people are still building small systems and they might want
a database; preferably one that hasn't been detuned to the extent
that it barely manages to run at all on such a platform.  Making
a whole lot of internal APIs 64-bit would be a pretty big hit for
a 32-bit platform --- more instructions, more memory consumed for
things like Datum arrays, all in a memory space that's not that big.

It seems especially insane to conclude that we should pull the plug
on such use-cases just to get rid of one obscure configure option.
If we were expending any significant devel effort on supporting
32-bit platforms, I might be ready to drop support, but we're not.
(Robert's proposal looks to me like it's actually creating new work
to do, not saving work.)

			regards, tom lane