VisiNotify slows down when a dial-up client is connected

Problem:

• Product Name: Visibroker
• Product Version: 5.2.1
• Product Component: VisiNotify
• Platform/OS Version: All

Notification service is running much slower when a dial-upclient is connected. The slow down is not experienced when testing without the dial up users.

The scenario is as follows:

There is a supplier and a consumer. The supplier, Visinotify and consumer are all on one machine. The events are sent to the consumer and no performance problems areexperienced. When a consumer is run on another host which is connected to the machine running VisiNotify through dial-up connection. Over the period of a half hour or so, the events to the consumer running on the machine where VisiNotify is running are now arriving much slower.

Resolution

This is caused by the TRANSIENT blocking event flow control mechanism of VisiNotify. The event queue overflows because of consistent large event flow. With the Transient Blocking event control mechanism, before starting an overflow handling mechanism such as rejecting or discarding events, the VisiNotify worker thread would block for a time interval specified by the property vbroker.notify.channel.maxOverflowDelay, and then reexamine the overflow condition. This slows down VisiNotify.  The default value for the vbroker.notify.channel.maxOverflowDelay is 1 msec.

To resolve this problem, please start the VisiNotify with the following command-line option:
vbroker.notify.channel.maxOverflowDelay=0