Programmer Reference : Redis : EsRedisHyperLogLogCommands
EsRedisHyperLogLogCommands
Description
Provides an API for the Redis HyperLogLog commands. A HyperLogLog is a probabilistic data structure used in order to count unique things (technically this is referred to as estimating the cardinality of a set).
This command group is accessed via EsRedisClient>>hyperLogLogs.
Class Methods
None
Instance Methods
pfadd:elements:
  Adds all the element arguments to the HyperLogLog data structure stored at the variable name specified as key.
    
     Arguments:
        aKey - <String> The key of the HyperLogLog.
        aCollectionOfElements - <Collection> The elements to add.
     Answers:
        <Integer> 1 if at least one HyperLogLog internal register was altered, 0 otherwise.
        <EsFuture> In async mode, a future that completes with the result.
pfcount:
  Return the approximated cardinality of the set observed by the HyperLogLog.
    
     Arguments:
        aCollectionOfKeys - <Collection of String> The keys of the HyperLogLogs to count.
     Answers:
        <Integer> The approximated number of unique elements observed via PFADD.
        <EsFuture> In async mode, a future that completes with the result.
pfmerge:sourceKeys:
  Merge multiple HyperLogLog values into a single one.
    
     Arguments:
        aDestKey - <String> The destination key.
        aCollectionOfSourceKeys - <Collection of String> The source keys.
     Answers:
        <String> 'OK'.
        <EsFuture> In async mode, a future that completes with the result.
Last modified date: 01/22/2026