I’m a big fan of accessing the database via services and there are some nice new features with database services in 11gR2. However I got a nasty shock when performing some patch maintenance with an 11.2.0.1 RAC system that had applications using services. Essentially I did not realise what happens to a service when you shutdown an instance for maintenance. Let me demonstrate:

This has the following configuration:

So the service is now online on the node where DBA1 (preferred node in definition) runs:

any examples I’ve seen, show what happens to a service when you perform shutdown abort. First lets see what our tns connection looks like:

Which gives the following in V$SESSION when you connect using this definition:

Lets abort the node:

Oh that’s not good. Look whats happened to my application:

Let’s bring everything back and try a different kind of shutdown This time using the following: