One, One database record!
Two, Two database record!
By default, when using datasources with JBoss, it does a count to validate a connection, both on creation and when it is requested from the connection pool. It looks something like:
select count(*) from x
Now, this can take take a while when working with tables containing 1.8 million rows and growing. That said, the datasource config file has two properties which can be set:
These allow you to specify something like
count 1 from x
which runs a good bit faster.