piece
The join: a pointwise GCounter join of every bucket cell plus the zero and overflow counters. Inherits the three lattice laws from GCounter, and is lossless — with distinct replicas, per-replica counts combine exactly, so the merged sketch equals the sketch of the combined stream.
Throws
if the two sketches' configuration (relativeAccuracy, minIndexedValue, maxIndexedValue) differs — the bucket indices of differently-configured sketches are incomparable.