Class StatisticsAggrFunctions.HllFieldReader

java.lang.Object
org.apache.drill.exec.expr.fn.impl.StatisticsAggrFunctions.HllFieldReader
All Implemented Interfaces:
DrillAggFunc, DrillFunc
Enclosing class:
StatisticsAggrFunctions

public static class StatisticsAggrFunctions.HllFieldReader extends Object implements DrillAggFunc
The log2m parameter defines the accuracy of the counter. The larger the log2m the better the accuracy. accuracy = 1.04/sqrt(2^log2m) where log2m - the number of bits to use as the basis for the HLL instance
  • Constructor Details

    • HllFieldReader

      public HllFieldReader()
  • Method Details

    • setup

      public void setup()
      Description copied from interface: DrillAggFunc
      Initialization for the beginning of the aggregation.
      Specified by:
      setup in interface DrillAggFunc
    • add

      public void add()
      Specified by:
      add in interface DrillAggFunc
    • output

      public void output()
      Specified by:
      output in interface DrillAggFunc
    • reset

      public void reset()
      Specified by:
      reset in interface DrillAggFunc