Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> Important: Oracle processes taking lots of CPU

Important: Oracle processes taking lots of CPU

From: New DBA <>
Date: Tue, 23 Nov 2004 02:57:08 -0800 (PST)
Message-ID: <>

Hi all,

Please forgive my ignorance if the details provided by me are not sufficient, or I'm not doing proper analysis.

11.5.8 on O/s HP-UX Risc 64 B.11.11

We are facing a unique problem. Lots of DB processes take close to 100% CPU and an overall CPU time of more than 500 mins. This happens with lots of different applications/forms. The problem doesn't happen all the time i.e. if the same form is run 10 times, only 1-2 faces that kind of problem.

With my limited knowledge I've been able to get the following details about the problem.

The DB processes take a huge amount of CPU time. This fact is not reflected in v$sesstat or the 10046 trace files. There are processes which take more than 500 mins. of CPU time, but the trace file doesn't account for even a tiny fraction of that.

When monitoring the process at the OS, the process takes close to 100% CPU all the time, but the CPU stats in v$sesstat doesn't increase.

I did a truss on the processes consuming 100% CPU and it shows the following line repeating infinitely:

select(2048, 0x800003fffdffb3d0, 0x800003fffdffb4d0, 0x800003fffdffb5d0, 0x800003fffdffb6d0) = 0

v$session_wait shows some wait event like "latch free", "db file sequential read" but with STATE = waited known time, but the seconds_in_wait keeps increasing while the process keeps taking 100% CPU all the while.

Please let me know if anyone has faced a similar issue. How do I find out what is the process doing which is eating up all the CPU?

I think that the problem is somehow at the O/S level, since trace files don't indicate anything wrong, same forms when run again, run without taking much CPU.

New DBA                 

Do you Yahoo!?
The all-new My Yahoo! - Get yours free!  
Received on Tue Nov 23 2004 - 04:54:25 CST

Original text of this message