Format of Metrics Messages

In order to consume and process a metrics messages, you must know its type and format. This section describes the general format of metrics messages and provides detailed information on the format of each type of metrics message.

Metrics messages are of type MapMessage. (A type of message whose body contains a set of name-value pairs. The order of entries is not defined.)

The message header has properties that are useful to applications. The type property identifies the type of metric message (and therefore its contents). It is useful if the same subscriber processes more than one type of metrics message for example, messages from the topics mq.metrics.broker and mq.metrics.jvm. The timestamp property indicates when the metric sample was taken and is useful for calculating rates or drawing graphs. The brokerHost, brokerPort, and brokerAddress properties identify the broker that sent the metric message and are useful when a single application needs to process metric messages from different brokers.
The body of the message contains name-value pairs, and the data values depend on the type of metrics message. The following subsections describe the format of each metrics message type.

Note that the names of name-value pairs (used in code to extract data) are case-sensitive and must be coded exactly as shown. For example, NumMsgsOut is incorrect; numMsgsOut is correct.

Broker Metrics

The messages you receive when you subscribe to the topic mq.metrics.broker have the type property set to mq.metrics.broker in the message header and have the data listed in Table 4-2 in the message body.

Table 4-2 Data in the Body of a Broker Metrics Message

Metric Name	Value Type	Description
numConnections	long	Current number of connections to the broker
numMsgsIn	long	Number of JMS messages that have flowed into the broker since it was last started
numMsgsOut	long	Number of JMS messages that have flowed out of the broker since it was last started
numMsgs	long	Current number of JMS messages stored in broker memory and persistent store
msgBytesIn	long	Number of JMS message bytes that have flowed into the broker since it was last started
msgBytesOut	long	Number of JMS message bytes that have flowed out of the broker since it was last started
totalMsgBytes	long	Current number of JMS message bytes stored in broker memory and persistent store
numPktsIn	long	Number of packets that have flowed into the broker since it was last started; this includes both JMS messages and control messages
numPktsOut	long	Number of packets that have flowed out of the broker since it was last started; this includes both JMS messages and control messages
pktBytesIn	long	Number of packet bytes that have flowed into the broker since it was last started; this includes both JMS messages and control messages
pktBytesOut	long	Number of packet bytes that have flowed out of the broker since it was last started; this includes both JMS messages and control messages
numDestinations	long	Current number of destinations in the broker

JVM Metrics

The messages you receive when you subscribe to the topic mq.metrics.jvm have the type property set to mq.metrics.jvm in the message header and have the data listed in Table 4-3 in the message body.

Table 4-3 Data in the Body of a JVM Metrics Message

Metric Name	Value Type	Description
freeMemory	long	Amount of free memory available for use in the JVM heap
maxMemory	long	Maximum size to which the JVM heap can grow
totalMemory	long	Total memory in the JVM heap

Destination-List Metrics

The messages you receive when you subscribe to a topic named mq.metrics.destination_list have the type property set to mq.metrics.destination_list in the message header.

The message body contains a list of map names. Each destination on the broker is specified by a unique map name (a name-value pair) in the message body. The type of the name-value pair is hashtable.

The name (in the name-value pair) depends on whether the destination is a queue or a topic, and is constructed as follows:

mq.metrics.destination.queue.monitored_destination_name
mq.metrics.destination.topic.monitored_destination_name

The value (in the name-value pair) is an object of type java.util.Hashtable . This hashtable contains the key-value pairs described in Table 4-4.

Table 4-4 Value of a Name-Value Pair

Key (String)	Value Type	Value or Description
`name`	String	Destination name
`type`	String	Destination type (`queue` or `topic`)
`isTemporary`	Boolean	Is destination temporary?

Notice that the destination name and type could be extracted directly from the metrics topic destination name, but the hashtable includes it for your convenience.

By enumerating through the map names and extracting the hashtable described in Table 4-4, you can form a complete list of destination names and some of their characteristics.

The destination list does not include the following kinds of destinations:

Destinations that are used by Message Queue administration tools
Destinations that the Message Queue broker creates for internal use

Destination Metrics

The messages you receive when you subscribe to the topic mq.metrics.destination.queue.monitored_destination_name have the type property mq.metrics.destination.queue.monitored_destination_name set in the message header. The messages you receive when you subscribe to the topic mq.metrics.destination.topic.monitored_destination_name have the type property mq.metrics.destination.topic. monitored_destination_name set in the message header. Either of these messages has the data listed in Table 4-5 in the message body.

Table 4-5 Data in the Body of a Destination Metrics Message

Metric Name	Value Type	Description
numActiveConsumers	long	Current number of active consumers
avgNumActiveConsumers	long	Average number of active consumers since the broker was last started
peakNumActiveConsumers	long	Peak number of active consumers since the broker was last started
numBackupConsumers	long	Current number of backup consumers (applies only to queues)
avgNumBackupConsumers	long	Average number of backup consumers since the broker was last started (applies only to queues)
peakNumBackupConsumers	long	Peak number of backup consumers since the broker was last started (applies only to queues)
numMsgsIn	long	Number of JMS messages that have flowed into this destination since the broker was last started
numMsgsOut	long	Number of JMS messages that have flowed out of this destination since the broker was last started
numMsgs	long	Number of JMS messages currently stored in destination memory and persistent store
avgNumMsgs	long	Average number of JMS messages stored in destination memory and persistent store since the broker was last started
peakNumMsgs	long	Peak number of JMS messages stored in destination memory and persistent store since the broker was last started
msgBytesIn	long	Number of JMS message bytes that have flowed into this destination since the broker was last started
msgBytesOut	long	Number of JMS message bytes that have flowed out of this destination since the broker was last started
totalMsgBytes	long	Current number of JMS message bytes stored in destination memory and persistent store
avgTotalMsgBytes	long	Average number of JMS message bytes stored in destination memory and persistent store since the broker was last started
peakTotalMsgBytes	long	Peak number of JMS message bytes stored in destination memory and persistent store since the broker was last started
peakMsgBytes	long	Peak number of JMS message bytes in a single message since the broker was last started
diskReserved	long	Disk space (in bytes) used by all message records (active and free) in the destination file-based store
diskUsed	long	Disk space (in bytes) used by active message records in destination file-based store
diskUtilizationRatio	int	Quotient of used disk space over reserved disk space. The higher the ratio, the more the disk space is being used to hold active messages

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	Oracle GlassFish Server Message Queue 4.5 Developer's Guide for Java Clients