Re: Odd numeric->float4/8 casting behaviour

From: Gregory Stark <stark(at)enterprisedb(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "PostgreSQL Hackers" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Odd numeric->float4/8 casting behaviour
Date: 2007-01-04 16:26:39
Message-ID: 87ps9uvjuo.fsf@enterprisedb.com
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"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Gregory Stark <stark(at)enterprisedb(dot)com> writes:
>> I believe this is happening because the numeric is being cast to float8 and
>> then the float4-float8 cross-data-type operator is being used. It seems like
>> it would be preferable to cast it to float4 and use the non-cross-data-type
>> operator. They're both marked as implicit casts so I'm unclear what decides
>> which gets used.
>
> Without having traced through the code, I think the fact that float8 is
> a "preferred type" is driving it. It's not clear whether we could
> change this without getting into a "can't resolve ambiguous operator"
> problem.

This is pre-operator-families, I thought "preferred type" was new with them.

Perhaps we should have preferred operators rather than preferred types?

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com

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