The Progress Open Application Server, or AppServer, is a brokered collection of 4GL engines that can execute Progress programs on the server in response to remote client requests. Each AppServer instance is identified by a unique name, and contains a broker that manages a pool of 4GL engine processes, each of which is available for processing client requests. See the Progress documentation for more information on setting up and using AppServers.

The client connects to an AppServer indirectly through the Progress Name Server. This provides for location transparency (and also provides the logical basis for load balancing and failover) since the clients do not need to know the host and port of the AppServer broker. The client only needs to know the unique name of the AppServer broker, which is used by the Name Server to determine the broker’s host and port.

Each AppServer instance can be configured to have its own set of parameter values such as the PROPATH, database connections, startup/shutdown procedures, and log files. These parameter values are specified in the configuration.properties file, located in the build/config directory, where build is the installation directory.

One extremely useful example of the AppServer is to improve the throughput speed of the processing-intensive task of running material requirements planning (MRP). The AppServer can distribute processing load across multiple threads, dramatically improving performance. For more information on MRP, see QAD Manufacturing User Guide.

As an example of how an AppServer can be used, this chapter includes instructions for setting up an AppServer to support enhanced MRP performance. See Using an Application Server to Run MRP (Example).

Before you can run applications using a Progress AppServer, the AppServer instance must be defined in AppServer Service Maintenance (36.19.1).