Major Description
We have a cube with more than ten distinct count measure, and use hll15 store the value, we found it is too slow of HyperLogLogPlusCounter, there are three methods will called frequentlly: merge/writeRegisters/readRegisters.
I found in kylin-1.5.x add a parameter 'singleBucket' to store the only one bucket which can optimize base cuboid.
However, in other step of cuboid building, it will slow down. I has modify the code to speed up the speed of three operation.