Is there any way to have the JBoss connection pool reconnect to Oracle when connections go bad?

Whilst you can use the old “select 1 from dual” trick, the downside with this is that it issues an extra query each and every time you borrow a connection from the pool. For high volumes, this is wasteful.

JBoss provides a special connection validator which should be used for Oracle:


This makes use of the proprietary ping() method on the Oracle JDBC Connection class, and uses the driver’s underlying networking code to determine if the connection is still alive.

However, it’s still wasteful to run this each and every time a connection is borrowed, so you may want to use the facility where a background thread checks the connections in the pool, and silently discards the dead ones. This is much more efficient, but means that if the connections do go dead, any attempt to use them before the background thread runs its check will fail.

See the wiki docs for how to configure the background checking (look for background-validation-millis).

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