11g is consuming 100% CPU

Hi, I have a problem with 11gR1(11.1.0.7).

The application is only runnig one query every 5 seconds and other query every 3 seconds. There are not other activity with the application over the database.
There is only one user in the application and the CPU consumption starts to rise up to 100%.

The execution time for each query is 30ms. Furthermore, this problem only occurs in 11gR1. In 10g database (10.2.0.2 or 10.2.0.4) is not happening. We have running the same application since 4 years and this never happened.

We update the statistics every day.

Anyone have any idea?
It happened something like this to someone?

Thanks in advance,
Federico

run statspack / awr and find out what is using the cpu

The CPU is used by these queries, there are a lot of buffer gets and the top wait event is latch: cache buffer chain.
The problem is that in other environment with Oracle 11g (11.1.0.7) and 10g these problems doesn't happen.
My question is if the optimizer of 11g can change the execution plan, even if the statistics doesn't be updated. And in one moment to another the Oracle may be resolve the execution plan in the wrong way - is just a guess.
The most rare is that these are optimized SQL statements.

Any idea?

I can't send the AWR (privacy policy), but if you need some part I will try.

Thanks,
Federico

Please, check this link http://www.eggheadcafe.com/software/...ue-in-11g.aspx
Is not the same issue, but is very strange

Operating System? is it Linux?

What do you see in v$session_wait ?

PAVB, thanks for the answer.

At the moment I don't have the information of v$_session_wait. I attach here an spreadsheet with AWR wait information and the SQL statements (please see rows in red and yellow).

Thank you,
Federico

I forgot it, the operating system is Linux.

The database has 2 nodes (RAC with failover) and it is configured with ASM.