Histogram is really a cumulative histogram

[defsprite]

In contrast to other prometheus clients (i.e. golang) the histogram does not use disjoint buckets but cumulative values (see https://github.com/prometheus/client_ruby/blob/master/lib/prometheus/client/histogram.rb#L28)

While this is also a nice way to collect metrics, it should be named as CumulativeHistogram and Histogram should behave as other client libraries do, as this can be confusing, especially when using quantile conversion.

[brian-brazil]

This is the same as other clients, just implemented a different way.

[grobie]

All Prometheus histograms are cumulative by definition. The golang library does this later in the Write() method. The ruby client library will follow suit once #36 is implemented (e.g. after the big rewrite).

[defsprite]

I stand corrected. Sorry for bugging you and thanks for the help!