HTTPS SSH

Build Status

A Metrics Reservoir implementation backed by HdrHistogram.

The artifacts are published to Bintray. If you're using gradle, use the jcenter() repository and put this in your build.gradle dependencies block:

compile 'org.mpierce.metrics.reservoir:hdrhistogram-metrics-reservoir:THE_LATEST_RELEASED_VERSION'

Or, if you're on Maven, see the Set Me Up button at https://bintray.com/bintray/jcenter and then add the dependency.

Then, use the following reservoir implementations when you create your Histogram or Timer instances:

  • HdrHistogramReservoir, a reservoir that accumulates its internal state forever
  • HdrHistogramResetOnSnapshotReservoir, a reservoir that resets its internal state on each snapshot (which is how reporters get information from reservoirs). See this article for when that is useful.

See http://hdrhistogram.org/ for why you want HdrHistogram as the underlying data structure, or watch Gil Tene talking about how latency is hard to measure well, or read this thread. The short version:

  • It's very fast (tens of nanoseconds to record)
  • It won't lose the outliers, which are the measurements you care about since latency is most assuredly not normally distributed
  • It doesn't allocate (except for the occasional resize, or you can pre-size your histograms to not allocate at all)

Also, check out some simple benchmarks of the various reservoir implementations.