Redis 4.x Cookbook

How to do it...

To understand how to use the HyperLogLog data type, take the following steps:

1. Open a Terminal and connect to Redis with redis-cli.
2. To count the distinct visitors for a restaurant called Olive Garden in Relp, we can count once by PFADD with one user ID:

127.0.0.1:6379> PFADD "Counting:Olive Garden" "0000123" 
(integer) 1 
 
127.0.0.1:6379> PFADD "Counting:Olive Garden" "0023992" 
(integer) 1 

3. Then, retrieve how many distinct visitors there are for this restaurant with the PFCOUNT command:

127.0.0.1:6379> PFCOUNT "Counting:Olive Garden" 
(integer) 2 

Another more complicated example, is that the you would like to show the unique number of visitors for Olive Garden in a week in Relp as an indication of weekly popularity; you can ...