Urgent problem : Plz help

Environment: Oracle 9.2.0.6 on SUSE linux 9 64-bit  

This problem happened today when our users started screaming about errors at the production database. I tried connecting the database through client and got the error  

ORA-00020: maximum number of processes (%s) exceeded  

I checked the value of the parameter PROCESSES which was 250. I set it to 300 and after the restart, I monitored the sessions and noticed the continuous increase in the number in the sessions where username is null. I think we may regard these as the orphan sessions. Surprisingly, the count for these sessions kept on increasing till it hit 300 and the clients started getting the same error.  

Considering the RAM, I've set the value of PROCESSES to 500 which may be the highest value I can set here. But I again notice that the count of these sessions with null username is continuously increasing. I doubt it will hit the max limit again.  

We don't have Connection pooling or MTS. Can anyone please give me the solution, its highly urgent!!!  

Thanks.

Khan  

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