Redis PFMERGE Command
The Redis PFMERGE command merges multiple HyperLogLogs into one HyperLogLog. The cardinality estimation of the merged HyperLogLog is calculated by performing a union of all the given HyperLogLogs.
Syntax
The basic syntax of the redis PFMERGE command is as follows:
PFMERGE destkey sourcekey [sourcekey ...]
Available versions
>= 2.8.9
Return value
Returns OK.
Examples
redis> PFADD hll1 foo bar zap a (integer) 1 redis> PFADD hll2 a b c foo (integer) 1 redis> PFMERGE hll3 hll1 hll2 "OK" redis> PFCOUNT hll3 (integer) 6 redis>
Other extensions