When you enable a connection, Integration Server initializes the connection pool, creating the number of connection instances you specified in the connection's Minimum Pool Size field when you configured the connection. Whenever an adapter service needs a connection, Integration Server provides a connection from the pool. If no connections are available in the pool, and the maximum pool size has not been reached, the server creates one or more new connections (according to the number specified in the Pool Increment Size field) and adds them to the connection pool. If the pool is full (as specified in Minimum Pool Size field), the requesting service will wait for Integration Server to obtain a connection, up to the length of time specified in the Block Timeout field, until a connection becomes available. Periodically, Integration Server inspects the pool and removes inactive connections that have exceeded the expiration period that you specified in the Expire Timeout field.

If initialization of the connection pool fails because of a network connection failure or some other type of exception, you can enable the system to retry the initialization any number of times, at specified intervals. For information about configuring connections, see Overview of Adapter for Apache Kafka Connections.