Re: anyway to flush the db_buffer_cache?

On Sat, 03 May 2003 16:56:21 GMT, "Ryan" <rgaffuri_at_cox.net> wrote:

>Im doing some tuning now and its hard to establish benchmarks if all the
>blocks are in memory. So for tuning purposes only Id like to flush them out
>to test different methods.
>
>Im not a good enough tuner to simply analyze a plan and no for certain what
>to do.
>

It doesn't really matter. The amount of logical I/O will remain the same whether the blocks are in memory or not. The goal of your tuning should be to reduce the logical I/O, not to get the hit ratio up. If that's your goal there more than enough tuning books around recommending what to do. Try it! just issue set autotrace on explain stats and run your query 2 times and see what happens. If you really want to flush the buffer cache there are 2 methods - run a full table scan on any table bigger than the buffer cache - bounce the database

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Sat May 03 2003 - 13:08:32 CDT