Usage Example: iquery -aq "fast_count(A)"
How does the fast count handle overlapping arrays?
In SciDB, in "Array.cpp: ConstChunk* ConstChunk::materialize() const "
if (!getArrayDesc().hasOverlap()) { materializedChunk->setCount(count); }
Therefore, the count is only set if there array does not have overlap. If the count is not set, the chunks are counted via an iterator.