| Measurement |
Description |
Measurement
Unit |
Interpretation |
| Used Connection |
Indicates the number of virtual connections to the server that are actively used
|
Number |
A Connection object encapsulates a virtual connection with the server. A connection typically represents a communication link between the application and the messaging server.
A connection is a fairly heavyweight object, and therefore most clients will use
one connection for all messaging. You may create multiple connections, if needed
by your application. The value of this measure therefore will indicate whether any applications require multiple connections to the EMS server.
|
| Connection used percentage |
Indicates the percentage of total connections to the server that are in use. |
Percent |
Ideally, this value should be high. A low ratio of used connections indicates that too many connections to the server are currently unused - i.e., are idle. Unused open connections are eventually closed, but they do consume resources that could be used for other applications. Too many idle connections therefore can accelerate the resource drain on the EMS server, thereby compelling other applications to contend for limited resources. A low value for this measure is hence a cause for concern. |
| Sessions |
Indicates the number of sessions on the server. |
Number |
A session represents a single-threaded context for sending and receiving messages. A session is single-threaded so that messages are serialized, meaning that messages are received one-by-one in the order sent. The benefit of a session is that it supports transactions. If the user selects transaction support, the session context holds a group of messages until the transaction is committed, then delivers the messages. Before committing the transaction, the user can cancel the messages using a rollback operation. A session allows users to create message producers to send messages, and message consumers to receive messages.
This measure is generally an indicator of how busy the EMS server is.
|
| Producers |
Indicates the number of producers communicating with the server.
|
Number |
Messages are structured data that one application sends to another. The creator of a message is known as a producer. Using the value reported by this measure, you can accurately figure out how many applications are sending messages to the queues on the server. |
| Consumers |
Indicates the number of consumers communicating with the server.
|
Number |
Messages are structured data that one application sends to another. The receiver of messages is known as a consumer. Using the value reported by this measure, you can accurately figure out how many applications are retrieving messages from the queues on the server. |
| Durables |
Indicates the number of messages for the durable subscriptions.
|
Number |
Each message consumer subscribes to a topic. When a message is published to that topic, all subscribed consumers receive the message. By default, subscribers only receive messages when they are active. If the messages are delivered when the subscriber is not available, the subscriber does not receive these messages. Java Message Service( JMS) specifies a way to remove the part of timing dependency by allowing subscribers to create durable subscriptions. Messages for durable subscriptions are stored on the server until the message expires or the storage limit is reached. Subscribers can receive messages from a durable subscription even if the subscriber was not available when the message was originally delivered. |