Data structures (bottom up)
- StepDouble: threadsafe
- By default, each step represent 1 min
- value operations are done by
DoubleWriter
- Within the same step, the returned value of
poll() will remain same. The value is reset at the each step
- Histogram: either
- hdr-based histrogram
TimeWindowPercentileHistogram
- fixed boundary histograms
TimeWindowFixedBoundaryHistogram
- Timer: has an instance of Histogram
- Meter: A named and dimensioned producer of one or more measurements. All the metrics construct we create in the application code, e.g., Counter, Timer, implements meter
- DatadogMeterRegistry: implements
MeterRegistry -> StepMeterRegistry.
- Maintains the list of meters
- Associates a instance of
Timer with a HistogramGauges, which translate histogram to the the percentile gauges (with the phi tag) we observe on DD
DatadogMeterRegistry.publish()
- Gets the API URI: by default is the public API. Normally we sent to dogstatd URL on 127.0.0.1
- Partition the
Meters in the registry to a nested list of Meters. By default, partition size is 10k
- All data in these 10k meters will be published in a single POST call
- By default, this method is triggered once per minute. See
PushMeterRegistry.start()