Re: Load test of new application - what to measure

Afternoon Gints,

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

Internal : 7 28 2051
External : 0113 231 2051

>>> Gints Plivna <gints.plivna_at_gmail.com> 01/18/06 03:30pm >>>

<BIG SNIP>

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, serial=>nnnn).

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 http://oracledba.ru/orasrp/.

Cheers,
Norman.

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