eG Monitoring
 

Measures reported by EgJbMQTopicTest

Topics are used in the publish-subscribe paradigm. When a client publishes a message to a topic, he/she expects that a copy of the message will be delivered to each client that has subscribed to the topic. However, if the client is not up, running and receiving messages from the topics, it will miss messages published to the topic. To get around this problem of missing messages, clients can start a durable subscription. This is like having a VCR record a show you cannot watch at its scheduled time so that you can see what you missed when you turn your TV back on. Similarly, messages meant for a durable subscriber are stored in the persistent cache even when the subscriber is inactive. These messages are delivered to durable subscribers when they connect to the server. Using the EgJbMQTopicTest test, continuous monitoring of the topics is possible.

This test auto discovers the topics on the JBoss AS/EAP server and reports the number of durable messages and the durable subscribers of the topic. This test also helps the administrators to keep track on the messages added into each topic and the messages delivered from each topic along with the processing rate of the messages from the topic. This way, administrators can figure out the topic that is currently subscribed by most of the subscribers!

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Durable_msg_count Indicates the number of durable messages currently in the topic. Number  
Durable_sub_count Indicates the number of durable subscribers to the topic. Number Messages meant for a durable subscriber are stored in the persistent cache even when the subscriber is inactive. These messages are delivered to durable subscribers when they connect to the server.
Max_topic_depth Indicates the maximum value of the number of messages in the topic since the start of the queue. Number  
Msg_process_rate Indicates the rate at which messages were being processed by the topic in the last measurement period. Msgs/Sec  
Non_durable_msg_count Indicates the number of non-durable messages currently in the topic. Number If the total number of durable subscribers is high, then we can expect the total durable messages to be stored on the server also to be relatively on the higher side.
Non_durable_sub_count Indicates the number of subscribers to the topic who are currently non-durable. Number  
Total_sub_count Indicates the total number of subscribers to a topic. Number  
msg_added_count Indicates the number of messages that were added to this topic during the last measurement period. Number  
msg_delivered_count Indicates the number of messages in this topic that have been delivered. Number A high value is desired for this measure.