When you enable a connection, the Integration Server initializes the connection pool, creating the number of connection instances you specified in the connection's Minimum Pool Size field. Whenever an adapter service needs a connection, the 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 Pool Increment Size) and adds them to the connection pool. If the pool is full (as specified in Maximum Pool Size), the requesting service will wait for the Integration Server to obtain a connection, up to the length of time specified in the Block Timeout field, until a connection becomes available. Periodically, the Integration Server inspects the pool and removes inactive connections that have exceeded the expiration period that you specified in Expire Timeout. For information about configuring connections, see Adapter Connections.