PFCOUNT

PFCOUNT is a Redis command used to retrieve the estimated number of unique elements in one or more HyperLogLog structures. It provides an approximate cardinality count with a typical error rate of 0.81%, making it highly efficient for large datasets while using minimal memory. When called with multiple HyperLogLog keys, PFCOUNT merges the data and returns the approximate count of the union, allowing for quick aggregation of unique elements across multiple sets.

Learn more from the following resources:

• @official@PFCOUNT