Re: Tunning Select and Where statements

Is there a way to tell the query to avoid the index? I have worked on a mainframe (Unisys DMSII) database where you can either process through the index only (if all the values you want are in the index), through the data via the index, or just through the table space itself.

You may also reply to jxs at wolpofflaw dot com (no spam).

Thanks.

Riccardo Ferrari wrote in message <7u4o7v$lpk$1_at_nslave1.tin.it>...
>I suppose you have a B-tree index on 'age'. In this case your index is not
>enough selective. Sometime a full scan of the table is better than an
access
>to the index followed by an access by ROWID to the table.
>In the second case you have a performance improvement because you avoid the
>second access by rowid. The name infact is already in the index segment.
>If your table is really large you should try to use an hash index on age to
>speed up your query.
>Ric
Received on Fri Nov 12 1999 - 09:00:18 CST