org.apache.hadoop.hive.ql.udf.generic

Class GenericUDAFComputeBitVectorFMSketch

java.lang.Object

org.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolver

org.apache.hadoop.hive.ql.udf.generic.GenericUDAFComputeBitVectorBase

org.apache.hadoop.hive.ql.udf.generic.GenericUDAFComputeBitVectorFMSketch

All Implemented Interfaces:

GenericUDAFResolver, GenericUDAFResolver2

public class GenericUDAFComputeBitVectorFMSketch
extends GenericUDAFComputeBitVectorBase

GenericUDAFComputeBitVector. This UDAF will compute a bit vector using FMSketch algorithm. The ndv_compute_bit_vector function can be used on top of it to extract an estimate of the ndv from it.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GenericUDAFComputeBitVectorFMSketch.GenericUDAFDateStatsEvaluator
static class	GenericUDAFComputeBitVectorFMSketch.GenericUDAFDecimalStatsEvaluator
static class	GenericUDAFComputeBitVectorFMSketch.GenericUDAFDoubleStatsEvaluator
static class	GenericUDAFComputeBitVectorFMSketch.GenericUDAFLongStatsEvaluator
static class	GenericUDAFComputeBitVectorFMSketch.GenericUDAFStringStatsEvaluator
static class	GenericUDAFComputeBitVectorFMSketch.GenericUDAFTimestampStatsEvaluator
static class	GenericUDAFComputeBitVectorFMSketch.NumericStatsEvaluator<V,OI extends PrimitiveObjectInspector>

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

GenericUDAFComputeBitVectorBase.DateStatsAgg, GenericUDAFComputeBitVectorBase.DecimalStatsAgg, GenericUDAFComputeBitVectorBase.DoubleStatsAgg, GenericUDAFComputeBitVectorBase.LongStatsAgg, GenericUDAFComputeBitVectorBase.NumericStatsAgg, GenericUDAFComputeBitVectorBase.NumericStatsEvaluatorBase<V,OI extends PrimitiveObjectInspector>, GenericUDAFComputeBitVectorBase.StringStatsAgg, GenericUDAFComputeBitVectorBase.StringStatsEvaluatorBase, GenericUDAFComputeBitVectorBase.TimestampStatsAgg

Constructor Summary

Constructors

Constructor and Description
GenericUDAFComputeBitVectorFMSketch()

Method Summary

Modifier and Type	Method and Description
GenericUDAFEvaluator	getEvaluator(TypeInfo[] parameters) Get the evaluator for the parameter types.

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

getEvaluator

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericUDAFComputeBitVectorFMSketch

public GenericUDAFComputeBitVectorFMSketch()

Method Detail

getEvaluator

public GenericUDAFEvaluator getEvaluator(TypeInfo[] parameters)
                                  throws SemanticException

Description copied from interface: GenericUDAFResolver

Get the evaluator for the parameter types. The reason that this function returns an object instead of a class is because it is possible that the object needs some configuration (that can be serialized). In that case the class of the object has to implement the Serializable interface. At execution time, we will deserialize the object from the plan and use it to evaluate the aggregations.

If the class of the object does not implement Serializable, then we will create a new instance of the class at execution time.

Specified by:

getEvaluator in interface GenericUDAFResolver

Overrides:

getEvaluator in class AbstractGenericUDAFResolver

Parameters:

parameters - The types of the parameters. We need the type information to know which evaluator class to use.

Throws:

SemanticException