Re: Load test of new application - what to measure

  • From: "Norman Dunbar" <norman.dunbar@xxxxxxxxxxxxxxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>, <gints.plivna@xxxxxxxxx>
  • Date: Wed, 18 Jan 2006 15:59:06 +0000

Afternoon Gints,

Norman Dunbar.
Contract Oracle DBA.
Rivers House, Leeds.

Internal : 7 28 2051
External : 0113 231 2051

>>> Gints Plivna <gints.plivna@xxxxxxxxx> 01/18/06 03:30pm >>>
>> Hello all!
>> I'd like to get some suggestions from experienced minds.


Statspack level 6 works for me. This allows collecting of stats on SQL
statements individually. You can drill down on these using
@?/rdbms/admon/sqlrep - very useful when you identify a 'big hitting'
statement in a normal report from statspack.

Additionally, I'd be running snapshots on about 5 minute intervals -
make sure your perfstats tablespace is big enough ! (On a Linux server
I've got 350 Mb locally managed tablespace whihc allows me to hold a
snapshot, level 6, taken every 15 minutes with an 'archive' 7 days long.
Anything older is binned automagically.

On top, I'd probably be looking at what's in V$SESSION_WAIT,
V$SYSTEM_EVENT and if necessary V$SESSION_EVENT to see what is holding
things up.

If there are any nasty surprises in a particular part of the system,
I'd get a user to position him/herself at that point and start tracing
with everything turned on - DBMS_SUPPORT.START_TRACE_IN_SESSION(sid=>
nn, serial=>nnnn, waits=>true, binds=>true) - trace through the problem
then turn tracing off - DBMS_SUPPORT.STOP_TRACE_IN_SESSION(sid=> nn,

You might need to install the DBMS_SUPPORT package and grant execute on
it to 'dba' at least. If I remember correctly its in
?/rdbms/admin/dbmssupp.sql and needs to run as a SYSDBA user.

The trace files can be (a) big and (b) a nightmare to scan, so get hold
of ORASRP to help analyze them. Highly recommended. Again, if memory
servers you can get this from


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