OPMN Uses High CPU When Monitoring a Large Set of Component Processes
(Doc ID 1913963.1)
Last updated on MARCH 15, 2023
Applies to:Oracle Fusion Middleware - Version 184.108.40.206.0 to 220.127.116.11.0 [Release Oracle11g]
Oracle Forms - Version 18.104.22.168.0 to 22.214.171.124.0 [Release 11g]
Information in this document applies to any platform.
The CPU usage raises when monitoring the OPMN managed processes to check their status, and gathering DMS metrics.
This can happen with any managed component, but in this case, the behavior is observed when the number of frmweb (Forms Runtime) processes is higher than 150 processes, although it will depend on the server load. As the number of processes to monitor grows, the CPU usage for the opmn process grows as well every time it checks their status and runtime metrics.
The problem has been seen in Forms and Reports installs because the number of processes to monitor by opmn can be bigger, but it can happen in general on any installation type.
Debugging the opmn child process with strace -f -p <pid> the following symptoms are seen:
a) An iteration through all the processes in /proc/<pid>
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