PFMERGE
Syntax
PFMERGE destkey [sourcekey [sourcekey ...]]
- Available since:
- 2.8.9
- Time complexity:
- O(N) to merge N HyperLogLogs, but with high constant times.
- ACL categories:
-
@write,@hyperloglog,@slow,
Merge multiple HyperLogLog values into a unique value that will approximate the cardinality of the union of the observed Sets of the source HyperLogLog structures.
The computed merged HyperLogLog is set to the destination variable, which is created if does not exist (defaulting to an empty HyperLogLog).
If the destination variable exists, it is treated as one of the source sets and its cardinality will be included in the cardinality of the computed HyperLogLog.
Return
Simple string reply: The command just returns OK.