Re: Indexes not used

From: Ralph Graulich <ralph_at_grauli.ch>
Date: Tue, 05 Mar 2002 18:37:43 +0100
Message-ID: <ralph-CF6943.18374305032002@doorway.ih.reiff.de>

Hi,

> In a different oracle instance (schema created by same third party
> software), the indexes are not being used. Full table scans are
> happening. Hash joins are used.

There are many different problems, which cause indexes being used in one or another way. The most common ones to check are:

What kind of optimizer is used (cost based / rule based)?
Are the tables fully analyzed (ANALYZE TABLE <tablename> COMPUTE STATISTICS)?
Is there any configuration directive in the init.ora file which prevents Oracle from using HASH_JOINS?
In case hints are used: Are they written correctly?

Regards
... Ralph ... Received on Tue Mar 05 2002 - 11:37:43 CST