Re: New version of money type

From: Theo Schlossnagle <jesus(at)omniti(dot)com>
To: Jim C(dot) Nasby <jimn(at)enterprisedb(dot)com>
Cc: Theo Schlossnagle <jesus(at)omniti(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: New version of money type
Date: 2006-09-16 21:37:41
Message-ID: 09D462F2-1D83-4519-9324-A56D151E612C@omniti.com
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On Sep 16, 2006, at 5:27 PM, Jim C. Nasby wrote:

> On Thu, Sep 14, 2006 at 11:12:14AM -0400, D'Arcy J.M. Cain wrote:
>> The benefit of the money type is speed. Because internal operations
>> are done on integers they can generally be handled by single CPU ops.
>> My tests on the 64 bit version show 10% to 25% improvement over
>> numeric
>> for many operations.
>
> Has anyone looked at changing numeric so that for numbers with less
> than
> 9 digits it stores/uses an int, and for between 10 and 18 digits it
> uses
> a bigint? Perhaps that would net every numeric user a speed
> improvement.

Would that pose indexing issues? It would also mean that when
joining two tables you'd have to handle some interesting type
conversion issues (at times). We had someone accidentally create a
largish table with userid as "numeric" and other tables are "bigint",
it was disastrous for performance (joining). I'd imagine that if the
above wasn't done cleverly, that performance problem would be repeated.

// Theo Schlossnagle
// CTO -- http://www.omniti.com/~jesus/
// OmniTI Computer Consulting, Inc. -- http://www.omniti.com/

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