HiveMQ JVM Metrics Plugin

The HiveMQ JVM Metric Plugin adds several additional metrics about the Java Virtual Machine to HiveMQ’s internal metric registry. This allows for a deeper insight on what is happening inside the Java Virtual Machine and provides interesting information on memory usage and other runtime metrics provided by the JVM running HiveMQ.

These metrics include information about:

• Memory usage

• Threads

• Class Loaders

• Garbage Collection

• Open Files

• Buffer Pool

These metrics can be accessed by using the JMX-Plugin or the Graphite Plugin.

Or you can use these metrics in your own HiveMQ plugin

Installation

1. Download the sources of a plugin and build it

2. Unzip the contents of your download

3. Copy the jar file to the plugins folder inside your HiveMQ folder.

Read more about installing and configuring plugins in the HiveMQ Plugin Documentation.

List of Metrics

The following metrics are added to HiveMQ when this plugin is installed.

BufferPool

Table 1. BufferPool metrics

Name	Description
com.hivemq.jvm.buffer-pool.direct.capacity	estimate of the total capacity of the buffers in the direct pool
com.hivemq.jvm.buffer-pool.direct.count	estimate of the number of buffers in the direct pool
com.hivemq.jvm.buffer-pool.direct.used	estimate of the memory that the Java virtual machine is using for the direct buffer pool
com.hivemq.jvm.buffer-pool.mapped.capacity	estimate of the total capacity of the buffers in the mapped pool
com.hivemq.jvm.buffer-pool.mapped.count	estimate of the number of buffers in the mapped pool
com.hivemq.jvm.buffer-pool.mapped.used	estimate of the memory that the Java virtual machine is using for the mapped buffer pool

ClassLoader

Table 2. ClassLoader metrics

Name	Description
com.hivemq.jvm.class-loader.loaded	number of classes that are currently loaded in the Java virtual machine
com.hivemq.jvm.class-loader.unloaded	the total number of classes unloaded since the Java virtual machine has started execution

File descriptors

Table 3. File descriptor metrics

Name	Description
com.hivemq.jvm.file-descriptor.ratio	ratio of currently open against max open files for this JVM

Garbage collector

Table 4. Garbage collector metrics

Name	Description
com.hivemq.jvm.garbage-collector.PS-MarkSweep.count	the total number of collections that have occurred
com.hivemq.jvm.garbage-collector.PS-MarkSweep.time	the approximate accumulated collection elapsed time in milliseconds
com.hivemq.jvm.garbage-collector.PS-Scavenge.count	the total number of collections that have occurred
com.hivemq.jvm.garbage-collector.PS-Scavenge.time	the approximate accumulated collection elapsed time in milliseconds

Memory

Table 5. Memory metrics

Name	Description
com.hivemq.jvm.memory.heap.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.heap.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.heap.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.heap.usage	ratio used / max
com.hivemq.jvm.memory.heap.used	the amount of used memory in bytes
com.hivemq.jvm.memory.non-heap.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.non-heap.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.non-heap.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.non-heap.usage	ratio used / max
com.hivemq.jvm.memory.non-heap.used	the amount of used memory in bytes
com.hivemq.jvm.memory.pools.Code-Cache.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.pools.Code-Cache.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.pools.Code-Cache.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.pools.Code-Cache.usage	ratio used / max
com.hivemq.jvm.memory.pools.Code-Cache.used	the amount of used memory in bytes
com.hivemq.jvm.memory.pools.Compressed-Class-Space.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.pools.Compressed-Class-Space.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.pools.Compressed-Class-Space.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.pools.Compressed-Class-Space.usage	ratio used / max
com.hivemq.jvm.memory.pools.Compressed-Class-Space.used	the amount of used memory in bytes
com.hivemq.jvm.memory.pools.Metaspace.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.pools.Metaspace.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.pools.Metaspace.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.pools.Metaspace.usage	ratio used / max
com.hivemq.jvm.memory.pools.Metaspace.used	the amount of used memory in bytes
com.hivemq.jvm.memory.pools.PS-Eden-Space.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.pools.PS-Eden-Space.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.pools.PS-Eden-Space.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.pools.PS-Eden-Space.usage	ratio used / max
com.hivemq.jvm.memory.pools.PS-Eden-Space.used	the amount of used memory in bytes
com.hivemq.jvm.memory.pools.PS-Old-Gen.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.pools.PS-Old-Gen.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.pools.PS-Old-Gen.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.pools.PS-Old-Gen.usage	ratio used / max
com.hivemq.jvm.memory.pools.PS-Old-Gen.used	the amount of used memory in bytes
com.hivemq.jvm.memory.pools.PS-Survivor-Space.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.pools.PS-Survivor-Space.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.pools.PS-Survivor-Space.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.pools.PS-Survivor-Space.usage	ratio used / max
com.hivemq.jvm.memory.pools.PS-Survivor-Space.used	the amount of used memory in bytes
com.hivemq.jvm.memory.total.committed	the amount of memory in bytes that is committed for the Java virtual machine to use
com.hivemq.jvm.memory.total.init	the amount of memory in bytes that the Java virtual machine initially requests from the operating system for memory management
com.hivemq.jvm.memory.total.max	the maximum amount of memory in bytes that can be used for memory management
com.hivemq.jvm.memory.total.used	the amount of used memory in bytes

Threads

Table 6. Thread metrics

Name	Description
com.hivemq.jvm.threads.blocked.count	current number of threads in "blocked" state in this JVM (A thread in the blocked state is waiting for a monitor lock to enter a synchronized block/method or reenter a synchronized block/method)
com.hivemq.jvm.threads.count	current number of threads in this JVM
com.hivemq.jvm.threads.daemon.count	current number of live daemon threads in this JVM
com.hivemq.jvm.threads.deadlock.count	current number of deadlocked threads in this JVM
com.hivemq.jvm.threads.deadlocks	collection of information about the currently deadlocked threads
com.hivemq.jvm.threads.new.count	current number of threads in "new" state (has not yet started) in this JVM
com.hivemq.jvm.threads.runnable.count	current number of threads in "runnable" state in this JVM (A thread in the runnable state is executing in the Java virtual machine but it may be waiting for other resources from the operating system such as processor)
com.hivemq.jvm.threads.terminated.count	current number of threads in "terminated" state (The thread has completed execution) in this JVM
com.hivemq.jvm.threads.timed_waiting.count	current number of threads in "timed_waiting" state in this JVM ( thread in the waiting state is waiting for another thread to perform a particular action with a specified positive waiting time/timeout)
com.hivemq.jvm.threads.waiting.count	current number of threads in "waiting" state in this JVM (A thread in the waiting state is waiting for another thread to perform a particular action without a timeout)

Contributing

If you want to contribute to HiveMQ JVM Metrics Plugin, see the contribution guidelines.

License

HiveMQ JVM Metrics Plugin is licensed under the APACHE LICENSE, VERSION 2.0. A copy of the license can be found here.