Distribution Summary¶

See Distribution Summary for the concept.

Distribution Summaries are created using the Registry, which will be set up as part of application initialization. For example:

public class Server {

  private final DistributionSummary requestSize;

  @Inject
  public Server(Registry registry) {
    requestSize = registry.distributionSummary("server.requestSize");
  }

Then call record when an event occurs:

  public Response handle(Request request) {
    requestSize.record(request.sizeInBytes());
  }
}

Note: If the amount recorded is less than 0 the value will be dropped.

Batch Updates¶

For very high-volume updates within a single thread, DistributionSummary exposes a batchUpdater that buffers updates and flushes them as a single operation. See Performance Tips for the cross-cutting guidance and Counter.batchUpdater for an annotated example.

Percentile Distribution Summary¶

Use a regular Distribution Summary unless percentile estimates are required.

Create one via the static builder:

public class Server {

  private final PercentileDistributionSummary requestSize;

  @Inject
  public Server(Registry registry) {
    requestSize = PercentileDistributionSummary.builder(registry)
        .withId(registry.createId("server.requestSize"))
        .build();
  }

  public void onRequest(Request request) {
    requestSize.record(request.bodyBytes());
  }
}

The builder also accepts a range via withRange(min, max) to bound the bucket set and reduce storage overhead — see the Javadoc for details.