We Just ran into a problem with our website. We are running a Oracle 12c database and using IIS 8 on a Windows 12 Azure server. ODP.NET is the provider we use. The website is build in C# and run as a 64bit web application.
For Whatever reason, Oracle doesn't release our connections, and after a while we got an Oracle Error :
ORA-12520: TNS:listener could not find available handler for requested type of server
We reviewed all of our connections string, adding :
Min Pool Size=10;Max Pool Size=100;Connection Lifetime=120;Connection Timeout=60;Incr Pool Size=5; Decr Pool Size=2
We more than double the MAX Process and Sessions that was defined in the Oracle configuration.
It's help but only in delaying the problem.
For now what we have done is a batch file which run every 10 minutes and kills all inactive sessions that are still there after 30 minutes (ALTER SESSION KILL....IMMEDIATE).
That's where we are, we have enable the ODP.NET trace and waiting to look at it tomorrow, but by this time, what can cause this problem?
Finally what I found in the ODP.NET Trace was
TID: dac (ERROR) Oracle error code=28002; Oracle msg=ORA-28002: the password will expire within 6 days
Seems that this Error doesn't stop the access to the DB but hang the session in the pool.
After we fixed that, all was back to normal.