Associating Connections with Threads

To associate connections with a thread, set the Associate With Thread attribute to true. The default is false. A true setting allows connections to be saved as ThreadLocal in the calling thread. Connections get reclaimed only when the calling thread dies or when the calling thread is not in use and the pool has run out of connections. If the setting is false, the thread must obtain a connection from the pool each time the thread requires a connection.

The Associate With Thread attribute associates connections with a thread such that when the same thread is in need of connections, it can reuse the connections already associated with that thread. In this case, the overhead of getting connections from the pool is avoided. However, when this value is set to true, you should verify that the value of the Max Pool Size attribute is comparable to the Max Thread Pool Size attribute of the thread pool. If the Max Thread Pool Size value is much higher than the Max Pool Size value, a lot of time is spent associating connections with a new thread after dissociating them from an older one. Use this attribute in cases where the thread pool should reuse connections to avoid this overhead.

You can set the Associate With Thread attribute in the following ways:

• Enter an Associate With Thread value in the Edit Connection Pool Advanced Attributes page in the Administration Console. For more information, click the Help button in the Administration Console.

• Specify the --associatewiththread option in the asadmin create-jdbc-connection-pool command. For more information, see the Sun GlassFish Enterprise Server v3 Reference Manual.

• Specify the associate-with-thread option in the asadmin set command. For example:

  asadmin set domain1.resources.jdbc-connection-pool.DerbyPool.associate-with-thread=true

  For more information, see the Sun GlassFish Enterprise Server v3 Reference Manual.