From: Andrew Sullivan <ajs@crankycanuck.ca>
To: pgsql-sql@postgresql.org
Subject: Re: Floating point type to store numbers
Date: Tue, 17 Apr 2007 16:53:18 -0400
Message-ID: <20070417205318.GC9094@phlogiston.dyndns.org> (raw)
In-Reply-To: <19968.63.118.86.10.1176842013.squirrel@www.88thstreet.com>
References: <4838.63.118.86.10.1176836034.squirrel@www.88thstreet.com>
<20070417190443.GA9094@phlogiston.dyndns.org>
<19968.63.118.86.10.1176842013.squirrel@www.88thstreet.com>
On Tue, Apr 17, 2007 at 04:33:33PM -0400, Radhika Sambamurti wrote:
> Andrew,
> This has been quite helpful. My main concern is CPU cost. Thanks for the
> input.
You're welcome. Are you sure your main concern should be CPU cost?
It's true that numeric is more costly that float in a lot of cases,
but I know at least one auditor who will refuse to certify results
from programs that anywhere use floating-point storage or calculation
on accounting data. The problem is really that you can get compound
errors -- very small rounding errors several times can turn out to be
a big problem. (One quick primer that can help you understand this
is at <http://www2.hursley.ibm.com/decimal/decifaq1.html;.)
A
--
Andrew Sullivan | ajs@crankycanuck.ca
The whole tendency of modern prose is away from concreteness.
--George Orwell
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To: pgsql-sql@postgresql.org
Cc: ajs@crankycanuck.ca
Subject: Re: Floating point type to store numbers
In-Reply-To: <20070417205318.GC9094@phlogiston.dyndns.org>
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