I have not. The original HLL paper does have some points in it about bias
corrections for small cardinalities, and I am not sure if those are
implemented in Druid's HLL implementation.
On Mon, Sep 24, 2018 at 8:49 AM Charles Allen
wrote:
> https://github.com/apache/incubator-druid/pull/5712
https://github.com/apache/incubator-druid/pull/5712 adds some great
functionality to the Datasketches hooks in Druid.
One thing noted in
https://datasketches.github.io/docs/HLL/HllSketchVsDruidHyperLogLogCollector.html
is the severe bias the druid HLL implementation shows at ~5k uniques being
fed
