When a DTM process or the Data Integration Service process runs a data transformation job, it requests a connection instance from a connection pool. If the DTM process or the Data Integration Service process requires a PowerExchange connection instance, it requests the connection instance from PowerExchange.
When PowerExchange receives a request for a connection to a Listener, it uses a connection in the pool that has matching characteristics, including user ID and password. If the pool does not contain a connection with matching characteristics, PowerExchange modifies and reuses a pooled connection to the Listener, if possible. For example, if PowerExchange receives a request for a connection for USER1 on NODE1 and finds only a pooled connection for USER2 on NODE1, PowerExchange reuses the connection, signs off USER2, and signs on USER1.
When PowerExchange returns a Listener connection to the pool, it closes any files or databases that the Listener had opened.
If you associate multiple database connection objects with the same Listener node name, PowerExchange combines the connections into a single pool. For example, if you associate multiple database connections to NODE1, a connection pool is used for all PowerExchange connections to NODE1. To determine the maximum size of the connection pool for the Listener, PowerExchange adds the
Maximum # of Connections
values that you specify for each database connection that uses the Listener.
If you want each database connection object to use a separate connection pool, define multiple NODE statements for the same PowerExchange Listener and associate each database connection object with a different Listener node name.
PowerExchange connection pooling does not reuse netport connections unless the user name and password match.