Loosing connection to Oracle Instance.

Hi.
We have Oracle 8.1.7.0 database which serves as a database for our ecommerce web site. The site runs on websphere apps server, uses ejbs, etc.
The oracle server has a tns listener and 3 instances. Life(heavily utilised), test(light load) and accounting(heavily utilised). Accounting instance has no web presence at all.

On average once every 10-14 days we are unable to connect to our life oracle instance. i.e the connection just times out. When I used sqlplus directly on the oracle server I am also unable to connect to the life instance. Stopping and starting tnslistener service does nothing. However I can still connect to the instance by using svrmgrl.exe from oracle/bin and run selects on any table. It worth noting that when the life instance goes down we could still connect to test and accounting instances with no probs via sqlplus or web interface.

Unfortunately I am only in early stages of DBA'ing and totally unsure as to what could be causing the problem? I don't really know where to start looking or what to change. The fact that I can't even connect via sqlplus on the oracle machine locally emphasises that may be something wrong with the odbc driver? or number of simultaneous connections oracle can handle? anyway to check this please? Or am I on the totally wrong path?

any help would be greately appreciated
thanks
Vlad Received on Mon Jun 03 2002 - 21:37:38 CDT