Re: Can Oracle redo logs be played back at the same rate that they were recorded ? (stress testing, capacity planning, modeling)

Hi!

> An idea that occurred to me to at least put a test instance under similar
> load as production could be to some how play a day or so worth of redo
logs
> into a test system, but at the rate that they were recorded. I presume
redo
> logs were invented for recovery, in which case you want them replayed
ASAP,
> but can any one think of a way to pace the replay to simulate a loaded
> Oracle system?

No, applying redologs only plays back the changes in redologs and in 9i with two-pass recovery, it doesn't even replay every change it finds in redos, only the ones it finds not written to datafiles. Also, selects, procedure executions and a lot more are not recorded in redos.

> All other ideas welcome e.g. tools for automating loading and modeling.

www.mercuryinteractive.com

It has tools for Oracle Applications load testing.

> In this case we have a ORACLE ERP application and we want to double or
> triple the number of orders being placed on it every month. What is the
> best way to predict what will happen to performance?

Generally, one way for replaying changes would be to sql_trace a session or system and use record option in tkprof to get all not-recursive commands out of it. The same could be done with sqlnet tracing as well, but parsing the trace files could be quite hard.

Also, if you want just database stress testing, you could use Apache Jmeter with JDBC.

Tanel. Received on Mon Dec 08 2003 - 13:59:47 CST