Re: Disable Buffering

Andrew Allen wrote:

> Daniel Roy wrote:
> > 1) If you have lots of time and complete ownership of the database,
> > shutdown and restart the database between queries.
> > 2) Otherwise, issue "alter system flush shared_pool" between each
> > query (only if there's no one else using the database please).
> >
> The only way to flush cash it to take the relevent tablespaces offline,
> then put them back online. But, as I said before, what is the point?
> You will not get any useful metrics from doing this.
>
> > If I were you, I'd instead run each query twice, and keep the stats
> > from the second run only. That way, you would only time the soft
> > parse, not the hard one and the physical i/o. To answer your question,
> > there's no way to tell Oracle to bypass the cache.
> >
> Better. I would recommend three or four runs after the first and
> average the results.
> --
> AjA

Really it depends on the application and the specific code being executed.

If something is run only rarely ... one try following a cold startup may be most appropriate. But if it is SQL that will be executed thousands of times a day by different transactions ... it should be tested only in the context of information in the cache matching the production environment.

Daniel Morgan Received on Wed Feb 26 2003 - 15:02:04 CST