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, AutoCloseable

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

Field Summary

Fields

Modifier and Type	Field and Description
protected PrimitiveObjectInspector	inputOI
protected StandardListObjectInspector	loi
protected Integer	nbins
protected double[]	quantiles

Constructor Summary

Constructors

Constructor and Description
GenericUDAFPercentileApprox.GenericUDAFPercentileApproxEvaluator()

Method Summary

Methods

Modifier and Type	Method and Description
GenericUDAFEvaluator.AggregationBuffer	getNewAggregationBuffer() Get a new aggregation object.
protected double[]	getQuantileArray(ConstantObjectInspector quantileOI)
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, getWindowingEvaluator, init, isEstimable, terminate

Methods inherited from class java.lang.Object

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

Field Detail

inputOI

protected PrimitiveObjectInspector inputOI

quantiles

protected double[] quantiles

nbins

protected Integer nbins

loi

protected transient StandardListObjectInspector loi

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

getQuantileArray

protected double[] getQuantileArray(ConstantObjectInspector quantileOI)
                             throws HiveException

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