disable buffer cache - very urgert !

I would like to disable the buffer cache. How to do that?
We have setup load test where connections with "same user activities" are
concurrently hitting the database. The problem with the "set of activities"
are same for all connections and worried whether the data will be buffered?
and it wont be real test for performance?
Thanks,
RamuYou can't disable it, but you can minimize it (sp_configure and "max server
memory") and/or you can
flush the buffer (DBCC DROPCLEANBUFFERS).
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
"Ramu" <Ramu@.discussions.microsoft.com> wrote in message
news:6113D3F2-8409-4874-A043-9E31A0D00213@.microsoft.com...
>I would like to disable the buffer cache. How to do that?
> We have setup load test where connections with "same user activities" are
> concurrently hitting the database. The problem with the "set of activities
"
> are same for all connections and worried whether the data will be buffered
?
> and it wont be real test for performance?
> Thanks,
> Ramu
>|||"Ramu" <Ramu@.discussions.microsoft.com> wrote in message
news:6113D3F2-8409-4874-A043-9E31A0D00213@.microsoft.com...
>I would like to disable the buffer cache. How to do that?
> We have setup load test where connections with "same user activities" are
> concurrently hitting the database. The problem with the "set of
> activities"
> are same for all connections and worried whether the data will be
> buffered?
> and it wont be real test for performance?
>
Testing with a cold cache is _very_ unrealistic. Testing with an unusually
warm cache may be somewhat unrealistic, but no load test is perfect.
Without real production data and a real production workload, you can only
use your load-test results for analyzing performance bottlenecks and
generating rough estimates of capacity and throughput.
David|||Ramu wrote:
> I would like to disable the buffer cache. How to do that?
> We have setup load test where connections with "same user activities" are
> concurrently hitting the database. The problem with the "set of activities
"
> are same for all connections and worried whether the data will be buffered
?
> and it wont be real test for performance?
> Thanks,
> Ramu
>
Query results ARE NOT CACHED, only the raw data pages from the
underlying tables are cached. SQL Server uses some very complex
algorithms for caching data to minimize disk reads in order to improve
performance. Since that's part of normal operation, it seems like you
would want that reflected in your load test. Regardless, you can't
disable it.
Tracy McKibben
MCDBA
http://www.realsqlguy.com