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Re: Question on selecting rows in table

From: JohnO <john.d.osborne_at_hp.com>
Date: Tue, 05 Nov 2002 21:49:59 GMT
Message-ID: <b2Xx9.39$Gv2.2099361@news.cpqcorp.net>

"Daniel Morgan" wrote:
> I have a real problem when people write "I need to" followed by a
description
> of what they "WANT" to do.

<etc.>
> Because I take strong exception with the thought that you actually "NEED"
to
> something in a specific way. Unless, of course, you are in a class and
your
> instructor has made this a requirement and you want someone else to do
your
> homework for you.
>
> Daniel Morgan
>

Okay - what I want to do is copy every row of a very large table to a flat file, or if necessary, multiple flat files, as quickly as possible. It appears to me that one approach might be to have multiple parallel threads copy portions of the table. However, this might be actually slower, because of the disk head latency if the table is contiguous. In any case, I can't test this theory if there is no reliable way to segment a table without looking at the data (because I want to solve this for the general case - any large table). For partitioned tables, I understand that I can select by partition, which may be the only case where there would be performance improvement.

I am working on a general-purpose utility which I expect will get extensive usage - this is not an academic exercise, but I want to investigate all possibilities I have time for, simply to find the fastest solution. If this approach is impossible or wrong, that's fine, but I have no way of knowing without asking the possibly dumb question or trying an experiment that may fail.

Sorry my phrasing bothers you so much, I don't want or need anyone to solve my "business" problem, I just wanted to know if a technical avenue I was looking into was a dead end, or I was overlooking something simple. Received on Tue Nov 05 2002 - 15:49:59 CST

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