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Re: query performance -- revised!

From: Brian Peasland <oracle_dba_at_remove_spam.peasland.com>
Date: Thu, 29 May 2003 13:22:07 GMT
Message-ID: <3ED6097F.A07F2C3F@remove_spam.peasland.com>

>I have corrected my syntax and there is

> still a threshold (43 ORs) at which it switches from using an index to
> using a table scan on the Address table.

When you add more "OR" statements, you will be returning more rows from the table. At some point, the optimizer decides that a full table scan is preferrable to an index scan based on the percentage of rows returned.

Cheers,
Brian

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Brian Peasland
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Received on Thu May 29 2003 - 08:22:07 CDT

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