It is assumed in this section that you are tuning the performance of a Message Agent that is running in continuous mode at a consolidated site.
Worker threads can be used by the Message Agent to apply incoming messages from remote users. This can improve throughput by allowing messages to be applied in parallel rather than serially.
The number of worker threads is set on the Message Agent command line, using the -w option. The default is to use no worker threads, so that all messages are applied serially. The maximum number of worker threads is 50.
The performance advantage will be most significant when the server is on a system with a striped drive array.
When worker threads are being used, messages from different remote users are applied in parallel. Messages from a single remote user are applied serially. For example, ten messages from a single remote user will be applied by a single worker thread in the correct order.
Deadlock is handled by re-applying the rolled back transaction at a later time.
Reading messages from the message system is single-threaded. Messages are read and the header information is examined (to determine the remote user and the correct order of application) before passing them off to worker threads to be applied.
Building messages and sending messages is single-threaded.