Re: Remove configure --disable-float4-byval and --disable-float8-byval

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Remove configure --disable-float4-byval and --disable-float8-byval
Date: 2019-11-02 15:26:59
Message-ID: 30490.1572708419@sss.pgh.pa.us
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Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
> On 2019-11-01 15:41, Robert Haas wrote:
>> On a related note, why do we store typbyval in the catalog anyway
>> instead of inferring it from typlen and maybe typalign? It seems like
>> a bad idea to record on disk the way we pass around values in memory,
>> because it means that a change to how values are passed around in
>> memory has ramifications for on-disk compatibility.

> This sounds interesting. It would remove a pg_upgrade hazard (in the
> long run).

> There is some backward compatibility to be concerned about.

Yeah. The point here is that typbyval specifies what the C functions
concerned with the datatype are expecting. We can't just up and say
"we're going to decide that for you".

I do get the point that supporting two different typbyval options
for float8 and related types is a nontrivial cost.

regards, tom lane

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