Oracle Tomcat Connection Problem

Question

Dear all,
We have Oracle as the back end and Java-Jsp-Struts as the front end for our project.For the last few days we are facing a strange problem and although we tried a lot we were not able to find even the cause of the problem
We have Oracle server and Webserver running on seperate machine. As this is a webbased solution , clients can take the pages by putting the URL in the browser. The problem is that the connection to the database is lost sometimes and we need to restart our apache tomcat service to get the connection again. Once it is restarted the pages work fine for sometime and after sometime the problem comes again. Sometimes the problem occures frequently and sometimes rarely.
Please help us as we tried a lot to troubleshoot but failed.
Whenever we are loosing connection, the database or listener seem to have no problem as they are running perfectly fine. Is there something that should be done in Tomcat for oracle connections? Or if multiple users are accessing the database at the same time is there something to do sothat the webserver is able to handle these multiple connections and update operations?
The error messages that we get are:
The network adapter could not establish the connection
or The TNS Listener could not resolve the SID given in the connection descriptor
If the error is the second one then sometimes it will vanish after sometime even without restarting thr tomcat service . But for the first one we must restart the service
All suggessions are welcome.
Regards,
Cochu.

Answer 1

Hi,
Thanks for your valuable suggession, but when I
tried to ping from webserver to db server, it was
pinging all the time and I am sure that the LAN
Connection is alright.
Regards,
Cochu.No, the fact that Oracle works at all says that your network connection between servers is not the problem.
When you say "connection to Oracle", it sounds like you literally mean a single connection to Oracle. You open the connection on startup, so if it's stale or lost or dropped you have to restart the web app. Is this true?
If it is, your solution is to use a database connection pool and rewrite the database code in such a way that you get a fresh connection out of the pool when request comes in, use it, and immediately close it in the same scope, returning it to the pool. Scope should be within a single transaction in a single method. You should keep a connection open only for as long as you need it for a request.
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