Probabilistic data structures give approximations of statistics such as
counts, frequencies, and rankings rather than precise values.
The advantage of using approximations is that they are adequate for
many common purposes but are much more efficient to calculate. They
sometimes have other advantages too, such as obfuscating times, locations,
and other sensitive data.
Probabilistic data structures are not available by default in the basic
Redis server, so you should install Redis Stack or Redis Enterprise,
both of which include probabilistic structures and other useful modules.
See
Install Redis Stack or
Install Redis Enterprise
for full installation instructions.