Automatic reconnection and resynchronization

When CICS® is connected to WebSphere® MQ and the queue manager stops, the CICS-WebSphere MQ adapter tries to reconnect after the stoppage has been detected. The connect request uses the same connect parameters that were used in the previous connect request.

If you have specified a single queue manager for the connection, CICS waits for 10 seconds after the stoppage is detected, and then tries to reconnect. If the queue manager has not been restarted within the 10 seconds, the connect request is deferred until the queue manager is restarted, when CICS reconnects automatically.

If you have specified a queue-sharing group for the connection, CICS tries to reconnect immediately when the stoppage is detected. The actions that CICS takes to restore the connection depend on whether there are outstanding units of work for the last queue manager, and the setting that you have specified for resynchronization.

If you have specified a queue-sharing group for the connection, you can select appropriate resynchronization actions for CICS by using the RESYNCMEMBER attribute of the MQCONN resource definition. Resynchronization takes place when the connection to WebSphere MQ is lost and CICS is holding outstanding units of work for the last queue manager. You can choose whether CICS waits to reconnect to the same queue manager, or whether CICS makes one attempt to reconnect to the same queue manager, but if that attempt fails, connects to a different eligible queue manager in the group. A queue manager is eligible for connection to a CICS region if it is currently active on the same LPAR as the CICS region.

Alternatively if WebSphere MQ supports group units of recovery for CICS, you can use the RESYNCMEMBER(GROUPRESYNC) option. With the GROUPRESYNC option, CICS connects to any local WebSphere MQ queue manager in the queue-sharing group and resolves all outstanding indoubt units of work regardless of which queue manager it was previously connected to. To resolve the outstanding units of work CICS must reconnect by using the same MQCONN resource definition that was used for the previous connection; for more information see How indoubt units of work are resolved by CICS.