Controlling the Flow of Data by Service Priority

You can exert significant control over the flow of data in an application by assigning service priorities using the PRIO parameter. The value of PRIO must be a number between 0 and 100. The higher the number, the higher the priority of the service to which it is assigned. Higher priority services are dequeued before lower priority services, but the system dequeues every tenth request in FIFO order to prevent a message from waiting indefinitely on the queue.

For instance, Server 1 offers Services A, B, and C. Services A and B have a priority of 50 and Service C has a priority of 70. A service requested for C will always be dequeued before a request for A or B. Requests for A and B are dequeued equally with respect to one another.

Note: A priority can also be changed dynamically with the tpsprio()call.

Characteristics of the PRIO Parameter

The PRIO parameter has the following characteristics:

Sample SERVICES Section Using Different Priorities

The following sample from the SERVICES section of a configuration file shows how priorities are assigned to services:

*SERVICES
A  SRVGRP=GRP1 PRIO=50 LOAD=60
A  SRVGRP=GRP2  PRIO=70 LOAD=30

In this example, different service-specific parameters are assigned to two server groups. Service A is assigned a priority of 50 and a load of 60 in server group GRP1, and a priority of 70 and a load of 30 in server group GRP2.