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I’ve used these log-linear history in a few pieces of code. There is some configurability in the abstract - you could choose a different logarithm base. In pra
by joeblubaugh 4y ago
I’ve used these log-linear history in a few pieces of code. There is some configurability in the abstract - you could choose a different logarithm base.
In practice none of the implementations seem to provide that. Within the each set of buckets for a given log base you have reasonable precision at that magnitude. If your metric is oscillating around 1e6 you shouldn’t care much about the variance at 1e2, and with this scheme you don’t have to tune anything to provide for that.
- heinrichhartman 4y agoThere are a large amount of subtle tradeoffs around the bucketing scheme (log, vs. log-linear, base) and memory layout (sparse, dense, chunked) the amount of configurability in the histogram space (circllhist, DDSketch, HDRHistogram, ...). A good overview is this discussion here: https://github.com/open-telemetry/opentelemetry-specification/issues/1776 https://github.com/open-telemetry/opentelemetry-specificatio... As for the circllhist: There are no knobs to turn. It uses base 10 and two decimal digits of precision. In the last 8 years I have not seen a single use-case in the operational domain where this was not appropriate.
- joeblubaugh 4y agoRight - it’s why I said “in the abstract.” You could do it and still have a log-linear format. Base 10 works great for real-world distributions. Thanks for making and ossing circllhist. I’ve been close by to the whole “what’s the OTel histogram going to be” discussion for the last many months and learned a lot from that. That discussion is what introduced me to circllhist and got me using them.
- heinrichhartman 4y agoGood to hear. I also learned a lot from this discussion!