Every now and then, Oracle Discoverer (10.1.2) throws a tantrum saying that the “Hard limit on the number of sessions” has been reached. It gets particularly annoying when this happens during the middle of the week and we are left with no choice but to schedule a downtime and restart the services.
What causes this error?
The number of sessions is specified in the opmn.xml file and it also there that the parameter can be edited to a desired value. Thought this by no means is a solution, it greatly reduces the frequency of occurrence of this error.
Recently, I’ve tried to monitor the number of sessions, which could help me predict when the limit might be reached and therefore schedule a restart during an off-peak time beforehand.
There are three numbers that I’m checking
1. On the Linux command line,
$ ps -ef | grep dis51ws | wc -l
2. On the command line again,
$ netstat -apn | grep unix | grep dis51ws | wc -l
3. The number of sessions as shown in the Oracle Enterprise Manager Application Server console.
Each of these produces a different value, however all of these values show an increase / decrease when a new session is opened / closed. Which of these values would be more likely to hit the limit specified in the xml file remains to be seen.
Once verified, a script can be created and scheduled to restart the services automatically.