Wow, I just realized I misstated things rather significantly.
We very much have tuple sketches in C++, but the python wrapper for them is
a work in progress. I thought I had it ready, but it turns out there are
some pretty significant limitations with the wrapper we're using (pybind11)
that I now
Yes, Druid does this on top of the specialized Tuple sketch called
ArrayOfDoublesSketch (in Java).
Each key in the sketch has an array of floating-point values associated
with it.
PostAggregator functions can convert these columns into means and
variances using org.apache.commons.math3.stat.descrip
