Class CountMinSketch

java.lang.Object
org.infinispan.server.resp.commands.countmin.CountMinSketch
@ProtoTypeId(6153) public final class CountMinSketch extends Object
A Count-Min Sketch implementation compatible with Redis CMS commands.

Count-Min Sketch is a probabilistic data structure that serves as a frequency table of events in a stream of data. It uses hash functions to map events to frequencies, but unlike a hash table, uses only sub-linear space at the expense of overcounting some events due to collisions.

Since:
16.2

  • Constructor Details

    • CountMinSketch

      public CountMinSketch(int width, int depth)
      Creates a Count-Min Sketch with specified dimensions.
      Parameters:
      width - number of counters in each row (determines error rate)
      depth - number of rows/hash functions (determines probability)

  • Method Details

    • getWidth

      @ProtoField(number=1, defaultValue="2000") public int getWidth()

    • getDepth

      @ProtoField(number=2, defaultValue="7") public int getDepth()

    • getCounters

      @ProtoField(number=3) public long[] getCounters()

    • getTotalCount

      @ProtoField(number=4, defaultValue="0") public long getTotalCount()

    • incrBy

      public long incrBy(byte[] item, long increment)
      Increments the count of an item by the specified amount.
      Parameters:
      item - the item to increment
      increment - the amount to add
      Returns:
      the estimated count after increment

    • query

      public long query(byte[] item)
      Returns the estimated count of an item.
      Parameters:
      item - the item to query
      Returns:
      the estimated count (minimum across all hash functions)

    • merge

      public void merge(CountMinSketch other, double weight)
      Merges another sketch into this one with a weight multiplier.
      Parameters:
      other - the sketch to merge
      weight - the weight multiplier for the other sketch
      Throws:
      IllegalArgumentException - if dimensions don't match