I'm new to c3p0, and confused about the use of :
c3p0.idle_test_period
In this link : HowTo configure the C3P0 connection pool
idleTestPeriod : Must be set in hibernate.cfg.xml (or hibernate.properties), Hibernate default:
0, If this is a number greater than 0, c3p0 will test all idle, pooled but unchecked-out
connections, every this number of seconds.
What is the purpose of this kind of test (idel, pooled connections), and the relationship between c3p0.idle_test_period and c3p0.timeout?
The database server may close a connection on its side after a certain amount of time - causing some error in your application, because it'll attempt to send a query on a connection which is no longer available on the server side.
In order to avoid this you can let the pool periodically check a connection (Think of a ping) for it's validity. This is what idle_test_period is for.
timeout is the timespan after which the pool will remove a connection from the pool, because the connection wasn't checked out (used) for a while and the pool contains more connections than c3pO.min_size.