Note about designing structure connections

XES associates a connection to a coupling facility structure with the task that issues the IXLCONN macro. When that task is ended, either normally or abnormally, the connection to the structure fails. The task that issued the IXLCONN macro is responsible for termination/cleanup and is accountable for all resources associated with the task.

This task association has several implications which require that you evaluate carefully your application design:

Should a task that has issued one or more IXLCONN requests terminate abnormally for some reason, then all the associated XES connection(s) will be terminated as a result of the termination. For example, if your task connects to several structures, each of which is required to support the task's function, and your task fails, all connections fail. This might be acceptable because your task would not have been able to provide any function without connectivity to all structures.
Should a task that performs both XES-related and non-XES-related functions fail, then both types of processing are disrupted. The failure of the single task causes a loss of capability with a greater scope than might be necessary.

IBM®, therefore, recommends that you evaluate your design with the following considerations:

Do not aggregate unrelated XES connections under the same task.
Do not aggregate XES connections under the same task with non-XES-related functions.