Oracle give use lots of performance views, not only for database only, but also some important data about the applications. As a DBA we should analyze those data, and show the data to others. For example, how to configure the database connection pool in application, the minimum and the maximum connects?
It seems DBAs cannot get any data about it, we should analyze the application log and then get the required information . But it's not ture, usually the application use connection pool, so the database connection is permanent to database, we can simply keep a history of the database connections, to see whether it always reachs the configured maximum connection.
Run the following SQL every 5 minutes, and keep the data into a table for further analyze.
select sysdate day, INSTANCE_NAME,
machine, username, count(*) conncount
from v$session, v$instance
group by machine, username, instance_name
Then we can display the last three days' data of the application host, it will tell us whether we should change the configuration.
It's a easy job, but it make us tuning the application connection based on data, not by somebody's personal experience.