SQL*Plus / SQL*Net Dead Connection Detection

Recently I came across the situation where I knew for a fact that my sessions to the database where dead because I pulled the power plug out of my application server for a failover test. But the sessions stayed visible in the database and kept their locks therefor the failover failed.

Now how is that possible?

First let me sketch the layout of the setup.

Suppose you have a vendor supplied application that runs on their middleware. That (more...)