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Application Metrics

DB2Rest provides a metrics endpoint that you can use diagnostically to examine the metrics collected by the running application. Navigating to /actuator/metrics displays a list of available meter names.


curl --request GET \
--url http://localhost:8080/actuator/metrics \
--header 'User-Agent: insomnia/9.2.0'


This will list the names of all the meters available to query.

HTTP/1.1 200
Content-Type: application/json
Transfer-Encoding: chunked

{
	"names": [
		"application.ready.time",
		"application.started.time",
		"disk.free",
		"disk.total",
		"http.server.requests",
		"http.server.requests.active",
		"jvm.buffer.count",
		"jvm.buffer.memory.used",
		"jvm.buffer.total.capacity",
		"jvm.classes.loaded",
		"jvm.classes.unloaded",
		"jvm.compilation.time",
		"jvm.gc.live.data.size",
		"jvm.gc.max.data.size",
		"jvm.gc.memory.allocated",
		"jvm.gc.memory.promoted",
		"jvm.gc.overhead",
		"jvm.gc.pause",
		"jvm.info",
		"jvm.memory.committed",
		"jvm.memory.max",
		"jvm.memory.usage.after.gc",
		"jvm.memory.used",
		"jvm.threads.daemon",
		"jvm.threads.live",
		"jvm.threads.peak",
		"jvm.threads.started",
		"jvm.threads.states",
		"logback.events",
		"process.cpu.time",
		"process.cpu.usage",
		"process.files.max",
		"process.files.open",
		"process.start.time",
		"process.uptime",
		"system.cpu.count",
		"system.cpu.usage",
		"system.load.average.1m",
		"tomcat.sessions.active.current",
		"tomcat.sessions.active.max",
		"tomcat.sessions.alive.max",
		"tomcat.sessions.created",
		"tomcat.sessions.expired",
		"tomcat.sessions.rejected"
	]
}

It is possible to drill down to view information about a particular meter by providing its name as a selector - for example, /actuator/metrics/jvm.memory.max.


curl --request GET \
--url http://localhost:8080/actuator/metrics/jvm.memory.max \
--header 'User-Agent: insomnia/9.2.0'


The response of this metrics query is shown below:

HTTP/1.1 200
Content-Type: application/json
Transfer-Encoding: chunked

{
	"name": "jvm.memory.max",
	"description": "The maximum amount of memory in bytes that can be used for memory management",
	"baseUnit": "bytes",
	"measurements": [
		{
			"statistic": "VALUE",
			"value": 5.419040765E9
		}
	],
	"availableTags": [
		{
			"tag": "area",
			"values": [
				"heap",
				"nonheap"
			]
		},
		{
			"tag": "id",
			"values": [
				"G1 Survivor Space",
				"Compressed Class Space",
				"CodeCache",
				"G1 Old Gen",
				"Metaspace",
				"G1 Eden Space"
			]
		}
	]
}