How do I configure a connection pool for a clustered environment?
A1:
Configuring a connection pool in a clustered environment requires the use of DataSource objects and a special multitier JDBC driver such as the WebLogic RMI driver. A connection pool in a clustered environment can act as a unified connection pool for any applications accessing the pool. If any WebLogic Server in the cluster fails, the connection of the client application will be seamlessly maintained without disruption by the other WebLogic Servers in the cluster.
Q2:
Is there any way to monitor database connections from the Administration Console?
A2:
The Administration Console does provide a means to monitor the JDBC connection pool. The Monitoring tab for a configured connection pool provides the statistics for different instances of the connection pool. Statistical attributes such as "Waiters High" give an idea of the number of client applications waiting for connections. The "Connections High" attribute identifies the maximum number of connections used from the pool. The value of this attribute monitored over a period of time can give you an idea of whether the connection pool is always stretched to the limit or not. Similarly, other attributes give an idea of the overall usage and hence the performance of the configured connection pool. You need to monitor and analyze these statistics over a period of time and usage to identify whether the configured connection pool is performing optimally.
Q3:
Does WebLogic have any transaction support for its JDBC drivers?
A3:
Yes. WebLogic Server provides a special JDBC driver, called the WebLogic JTS driver or literally weblogic.jdbc.jts.Driver, that provides transactional support for all server-side applications deployed on WebLogic that access databases using the JDBC driver. Since the JTS is a separate driver, you need to configure a separate connection pool that uses the WebLogic JTS driver. The JTS driver supports all the transaction attributes used by the WebLogic Server and is based on the XA transaction standards.
