Using multithreading in the Java plug-in server

In previous releases, the Java plug-in server created a thread to handle each RPC connection as it was received from the AR System server, often creating many threads. If a connection failed, the plug-in server programmatically shut down the plug-in instances associated with the thread for that connection, often losing data in the process.

To improve performance, the Java plug-in server now uses a configurable pool of worker threads to handle RPC calls. The pool and its associated plug-in instances are created at startup, rather than as RPC calls are received. If a connection fails, the plug-in instances associated with the thread remain instantiated and can still process calls from other connections.

When an RPC call is received from the AR Server, a selector thread adds the call to the worker thread task queue. By default, the system uses two selector threads. To prevent bottlenecks, you can increase the number of selector threads by using the Number Of Selector Threads field on the AR System Administration:Plugin Server Configuration form.

Whenever a worker thread is free, it starts processing the next request in the task queue. By default, the pool contains five worker threads. To prevent bottlenecks, you can increase the number of worker threads by using the Number Of Core Threads field on the AR System Administration:Plugin Server Configuration form.

An unlimited number of tasks can be added to the worker thread task queue. To be notified when too many tasks accumulate in the queue, you can specify a task threshold. When the threshold is exceeded, a message is logged in the arjavaplugin.log file. This enables you to avoid potential queue bottlenecks by creating more worker threads in a timely fashion.

To specify the task threshold, use the Work Queue Task Threshold field on the AR System Administration:Plugin Server Configuration form.

To specify how frequently the system checks to see whether the task threshold has been exceeded, use the Work Queue Monitor Log Interval field on the AR System Administration:Plugin Server Configuration form.