Re: Analyze problem?

From: Wayne Straughn <Wstraughn_at_hotmail.com>
Date: Sat, 21 Jul 2001 21:31:07 GMT
Message-ID: <tkc9k48gsft0f2@corp.supernews.com>

Hi Andrew

When you delete the cost based optimizer statistics for a table, it forces the optimizer to revert to a
rules based mode when evaluating sql using that table. The rule based optimization may have an execute path utilizing indexes which were not used
in the cost based mode.

Wayne

Little Prince <milan1810_at_geocities.com> wrote in message news:9i3lam$24818_at_ctmsun0.macau.ctm.net...
> I use ANALYZE...COMPUTER STATISTICS command to analyze two tables which
are
> used in a DELETE statement in a batch job. The performance of the job
> obviously drops a lot. The execution time is server times longer than
> before. But, after I use ANALYZE...DELETE STATISTICS to remove the
> statistics, the execution time of the job is much shorter. Anyone can give
> me some advices? As I know statistics can improve performance, why is my
> case?
>
> Andrew
>
>
Received on Sat Jul 21 2001 - 16:31:07 CDT