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You can We will use the following examples:

Table of Contents
excludeSee also

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example to show how you can measure Java garbage collection with Prometheus.

GarbageCollector statistics is one of the of metrics that the Java/JVM client library exposes.

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The GarbageCollector statistics comes from GarbageCollectorMXBean, and is exposed as the jvm_gc_collection_seconds summary.
In particular, jvm_gc_collection_seconds_count is responsible for the number of GCs, and jvm_gc_collection_seconds_sum  deals with for how long they were taken.

These are the counters, so we can take a rate:

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We can see that PS Scavenge is happening once every 2 seconds or so, and PS MarkSweek is rare. You can have a question  might ask which of those are the young generation and which the old/tenured, but this is not something the JVM exposes so you have to know this in your setup given the name.

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Finally, using rate(jvm_gc_collection_seconds_sum[1m]) you can see what proportion of time each type of GC is taking up, which per the previous numbers is under 0.1% which is not a concern at all.

See also

Configuring Prometheus Exporters

JVM metrics