Redis HyperLogLog: PFADD
Redis PFADD Command
Redis PFADD command is used to add all the element arguments to the HyperLogLog data structure stored at the key name specified as the first argument.
Here are some common uses and scenarios for the "PFADD" command:
- Approximate Cardinality: Adds elements to a HyperLogLog data structure to approximate the cardinality (unique count) of a set.
- Memory Efficiency: Provides a memory-efficient way to estimate the number of unique elements in large datasets without storing all elements.
- Distinct Count Estimation: Useful for counting distinct items in streams of data, such as unique visitors to a website or unique events in a log.
- Big Data Analysis: Helps in big data analysis scenarios where precise counts are not required, but approximate counts are sufficient.
Syntax:
PFADD KEY_NAME ELEMENTS_TO_BE_ADDED
Available since
2.8.9.
Return Value
Integer reply, 1 or 0.
Return Value Type
Integer
Example: Redis PFADD
redis 127.0.0.1:6379> PFADD mykey a b c d e f g h i j (integer) 1 redis 127.0.0.1:6379> PFCOUNT mykey (integer) 10