High parsing with Siebel and Oracle RAC 10gR2

Question

Hi all,
I'm working for a company that uses Siebel 8 with a 2 nodes RAC 10gR2. 70GB SGA with assured minimum values for shared pool 16GB, 50GB db buffer cache and the rest distributed among the other pools.
In the last weeks we are facing a very annoying issue in our production system, at random times we have a very high concurrency peak with contention events like:
- cursor: pin S wait on X
- latch: library cache
and a performance problem as a consequence.
I have read all the documents on metalink about these types of waiting events and how to troubleshoot it, but I can't get rid of this problem.
We have dynamic SGA configured, but we haven't had any resizes in the last weeks.
We didn't have many "version count" for query, we are about <40.
In the AWR I have noticed that we have very high parsing (in most cases query execute=query parse). We have talked to our Siebel support team to propose them the use of CURSOR_SHARING=FORCE, but they told us that it's unsupported.
We have increased the parameter session_cached_cursors from 50 to 1000, but in the last days the problem has even got worse.
I suppose that the solution could be reducing the parse count and elapsed parse time, but without changing the CURSOR_SHARING parameter and not much help from Siebel support, I don't know how to achieve this.
Does anyone have any idea?

Answer 1

The only way you can reduce the number of parses is to fix Siebel (in other words - not much you can do).