Request of a setting on Datapower to define a minimum number of connections

Currently, the MQ connections are controlled by the following settings in mq-qm in DataPower:-

(1) total connection limit = maximum number of MQ connections

(2) initial connection number = the initial number of MQ connections when the mq-qm object is up

There is no setting to “maintain” (not initiate) connection in connection pool. Even customer has set a high value of initial connection number, the number of connections may drop below the initial connection number after a less transactions period. This is an expected behaviour of the Datapower with the setting of cache-timeout value. When an inactive connection reaches cache-timeout threshold, the dynamic connection is removed from the cache.

 When there is sudden burst of incoming messages and there are insufficient connections available in the connection pool, the Datapower will create new connection(s) to handle the messages.  That action consumes additional system resources, thus has performance impact to the MQ server and Datapower appliance. Customer has observed messages process time increase during this period.  

 An alternative is to set the cache-timeout value as zero so the connections will never be expired and removed from the connection pool. However, connections in the connection pool may become invalid (stale connection) due to the network/firewall issue. With zero cache-timeout value, invalid connections will never be removed and recreated.  As a result, the number of invalid connections will increase and finally affects the communication between Datapower appliance and MQ server. 

 With the above reasons, we would like Datapower to have a setting to maintain a minimum number of connections in the connection pool.