Need help understanding a performance problem

I have a small instance which is a clone of the production database, except for one table which contains blobs. The cloned instance is being used for testing a new release of the application (which is written in Powerbuilder). The cloned instance also sits on a smaller server (Sun E250 vs. E4500 for the prod db).

The testing users are complaining about very long delays during certain operations. In monitoring the instance, it has some wait event stats that are very different from the production. The biggest difference is with db_file_sequential_read. Here's some numbers:

                              TEST INSTANCE    PRODUCTION INSTANCE
                               (8-10 users)     (50-60 users)
                              -------------    -------------------

buffer busy waits                36                   2
control file parallel write    12493               10151
control file sequential read     116                 145
db file parallel read             13                 0
db file parallel write           390                 255
db file scattered read         23669               36038
db file sequential read       753289               16729

Something obviously is very "off" in the test instance, but I'm not sure where to start looking. A web search for 'db file sequential read' didn't turn up much.

Would a dropped index cause this?

Thanks,
Harry Boswell Received on Thu Jul 17 2003 - 10:18:37 CDT