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Re: METALINK and OWS

From: Rachel Carmichael <carmichr_at_hotmail.com>
Date: Sun, 11 Jun 2000 23:06:57 GMT
Message-Id: <10525.108573@fatcity.com>


WHOA! Slow down before you drop the indexes. Indexes are not totally useless! It very much depends on the queries you run against your database. If you are doing a mixture of queries, where some return single rows or a very small subset of data, and some return a large number of rows, you still should keep the indexes for the first type of query.

Rachel

>From: Nicholas Tufar <ntufar_at_chemist.gen.tr>
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: Re: METALINK and OWS
>Date: Sun, 11 Jun 2000 14:17:51 -0800
>
> >
> > Nicholas,
> >
> > Sorry... I thought most people knew this. Oracle says that if a query
>will
> > return more than 20% of the rows of a table, it will use a full table
>scan.
> > So you DON'T tune it to use an index. In fact, as of 8i, I believe
>Oracle
> > now recommends that if a query returns as little as 3-5% of a table, a
>full
> > table scan is the way to go.
>
>A very valuable piece of information. How did I miss it!
>Now I know what I am going to do on Monday. I had a feeling that
>all those indeces are useless, now I know why they are.
>Thank you very much.
>
>Nicholas
>--
>Author: Nicholas Tufar
> INET: ntufar_at_chemist.gen.tr
>
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Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com Received on Sun Jun 11 2000 - 18:06:57 CDT

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