org.apache.hadoop.hive.ql.udf.generic
Class GenericUDAFPercentileApprox.GenericUDAFPercentileApproxEvaluator

java.lang.Object
  org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator
      org.apache.hadoop.hive.ql.udf.generic.GenericUDAFPercentileApprox.GenericUDAFPercentileApproxEvaluator

All Implemented Interfaces:

Closeable

Direct Known Subclasses:

GenericUDAFPercentileApprox.GenericUDAFMultiplePercentileApproxEvaluator, GenericUDAFPercentileApprox.GenericUDAFSinglePercentileApproxEvaluator

Enclosing class:

GenericUDAFPercentileApprox

public abstract static class GenericUDAFPercentileApprox.GenericUDAFPercentileApproxEvaluator
extends GenericUDAFEvaluator

Construct a histogram using the algorithm described by Ben-Haim and Tom-Tov, and then use it to compute an approximate percentile value.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator

GenericUDAFEvaluator.AbstractAggregationBuffer, GenericUDAFEvaluator.AggregationBuffer, GenericUDAFEvaluator.AggregationType, GenericUDAFEvaluator.Mode

Constructor Summary

GenericUDAFPercentileApprox.GenericUDAFPercentileApproxEvaluator()

Method Summary

GenericUDAFEvaluator.AggregationBuffer	getNewAggregationBuffer() Get a new aggregation object.
void	iterate(GenericUDAFEvaluator.AggregationBuffer agg, Object[] parameters) Iterate through original data.
void	merge(GenericUDAFEvaluator.AggregationBuffer agg, Object partial) Merge with partial aggregation result.
void	reset(GenericUDAFEvaluator.AggregationBuffer agg) Reset the aggregation.
Object	terminatePartial(GenericUDAFEvaluator.AggregationBuffer agg) Get partial aggregation result.

Methods inherited from class org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator

aggregate, close, configure, evaluate, init, isEstimable, terminate

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GenericUDAFPercentileApprox.GenericUDAFPercentileApproxEvaluator

public GenericUDAFPercentileApprox.GenericUDAFPercentileApproxEvaluator()

Method Detail

merge

public void merge(GenericUDAFEvaluator.AggregationBuffer agg,
                  Object partial)
           throws HiveException

Description copied from class: GenericUDAFEvaluator

Merge with partial aggregation result. NOTE: null might be passed in case there is no input data.

Specified by:

merge in class GenericUDAFEvaluator

partial - The partial aggregation result.

Throws:

HiveException

terminatePartial

public Object terminatePartial(GenericUDAFEvaluator.AggregationBuffer agg)
                        throws HiveException

Description copied from class: GenericUDAFEvaluator

Get partial aggregation result.

Specified by:

terminatePartial in class GenericUDAFEvaluator

Returns:

partial aggregation result.

Throws:

HiveException

iterate

public void iterate(GenericUDAFEvaluator.AggregationBuffer agg,
                    Object[] parameters)
             throws HiveException

Description copied from class: GenericUDAFEvaluator

Iterate through original data.

Specified by:

iterate in class GenericUDAFEvaluator

parameters - The objects of parameters.

Throws:

HiveException

getNewAggregationBuffer

public GenericUDAFEvaluator.AggregationBuffer getNewAggregationBuffer()
                                                               throws HiveException

Description copied from class: GenericUDAFEvaluator

Get a new aggregation object.

Specified by:

getNewAggregationBuffer in class GenericUDAFEvaluator

Throws:

HiveException

reset

public void reset(GenericUDAFEvaluator.AggregationBuffer agg)
           throws HiveException

Description copied from class: GenericUDAFEvaluator

Reset the aggregation. This is useful if we want to reuse the same aggregation.

Specified by:

reset in class GenericUDAFEvaluator

Throws:

HiveException