By default, when you use WebSphere MQ to store state, any connections from the control terminal of the AggregateRequest node to the AggregateReply node are ignored. For these connections to be active, create the MQSI_AGGR_COMPAT_MODE environment variable in the broker's environment. By default, the environment variable does not exist. When you create this environment variable, connections from the AggregateControl node are active, regardless of the value of the environment variable.
When the MQSI_AGGR_COMPAT_MODE environment variable has not been created, the default behavior for aggregation fan-out flows is used. If the control terminal of the AggregateControl node is connected to the in terminal of the AggregateReply node, either directly or indirectly, this connection is ignored and no control message is sent.
If the MQSI_AGGR_COMPAT_MODE environment variable is created, the default behavior for aggregation fan-out flows is not used, allowing you to send control messages from the AggregateControl node to the AggregateReply node, but this configuration might have an adverse effect on performance.
To create the MQSI_AGGR_COMPAT_MODE variable to allow connections between AggregateControl and AggregateReply nodes to be recognized:
Windows:
export MQSI_AGGR_COMPAT_MODE=true
MQSI_AGGR_COMPAT_MODE=true