So, if your application experiences connection timeouts because of a database connection leak, the stack traces may not help you. Just like an out-of-memory exception due to a memory leak the stack trace has information about the victim, but not the root cause. So where can you go to find the leak?
Even though database connection leaks are a client problem, you can find help from the database server. On the database server, look at connections per process per database to get a rough estimate of the size of each pool:
This is a good thing to remember, particularly if you have a busy system.