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Re: Why are my indexes being ignored?

From: Thater, William <ThaterW_at_telergy.net>
Date: Fri, 29 Jun 2001 08:18:29 -0700
Message-ID: <F001.0033D8A9.20010629075244@fatcity.com>

"Carle, William T (Bill), NLCIO" wrote:
>
> Hi,
>
> I created an index on a table. The table has about 83,000 rows. The
> index is a simple index on one field, 35 different values of the index. I
> analyzed the table and I analyzed the index, trying it both with a histogram
> and without a histogram. No matter how I do it, it does a full table scan.
> Any ideas why? I know I can use a hint, but it seems to me that it ought to
> use the index.

how many rows are you returning? if i remember right, and if i don't i'm sure i'll be reminded;-), if you return more than a certain % of the table it does a full table scan even if there are indexes.

--
Bill "Shrek" Thater   Certifiable ORACLE DBA
Telergy, Inc.            thaterw_at_telergy.net
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You gotta program like you don't need the money,
You gotta compile like you'll never get hurt,
You gotta run like there's nobody watching,
It's gotta come from the heart if you want it to work.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"It's not a bug. It's an undocumented feature"
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Thater, William
  INET: ThaterW_at_telergy.net

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Received on Fri Jun 29 2001 - 10:18:29 CDT

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