MAXTASKS={
maximum_tasks|
5}

If resource usage by PowerExchange Listener tasks exceeds the resources available for the PowerExchange Listener, the Listener abends. In this case, you can try decreasing the MAXTASKS value to run fewer concurrent tasks. Although tasks can have different resource requirements, this statement can help limit the amount of resources that are used for PowerExchange Listener tasks and prevent these types of abends.
The MAXTASKS parameter is not intended to be an operating system performance and tuning parameter. To balance the workload of multiple concurrent tasks, use the workload management facility of the operating system, for example, Workload Management (WLM) on z/OS.
If you use PowerExchange tuning features that result in multiple threads and PowerExchange Listener subtasks, such as pipeline partitioning or multithreaded processing, you might need to increase the MAXTASKS value if PowerExchange processing slows or hangs. You also might need to increase this value if you add PowerCenter workflows. After the number of concurrent tasks reaches the MAXTASKS limit, the PowerExchange Listener rejects requests for additional tasks with message PWX- 00609:
PWX-00650 10.3.0.111:3720 : Listener 10.33.40.42 -> 10.3.0.1 on port 1234 socket 51
PWX-00609 Listener has temporarily stopped accepting connections.
When the number of the concurrent tasks drops below the MAXTASKS limit once again, the PowerExchange Listener begins accepting requests for additional tasks.
If you use connection pooling, ensure that the MAXTASKS value is large enough to accommodate the size of the connection pool.
The maximum number of concurrent tasks that a PowerExchange Listener can support might be substantially less than 255 because of operating system resource constraints, such as virtual storage limitations on z/OS.