We recently did an Oracle DB upgrade and migrated the database from Unix to Linux for Siebel. Couple of days after, there was a big performance issue in Production environment which brought down the database. Client DBA team identified the problem as HUGE page parameter being off. Once the huge page parameter in Linux was turned on, issue got resolved.
However, we never encountered the issue in other environments with HUGE page parameter turned off, not even during the performance testing. the issue should have occurred in We reran the performance testing with rigorous load in performance test environment with similar to Production database size and HUGE page parameter off, but still the environment was stable. We think that we might be missing something important in performance testing.
It will be a great help if you could provide some insight on what could be the cause.
We checked # of insert/update/delete statements in performance and production environment were almost same.
# of database connections in performance environment were less compared to production environment. Could that be the cause?