Package org.apache.datasketches.hive.hll
Class DataToSketchUDAF
- java.lang.Object
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- org.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolver
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- org.apache.datasketches.hive.hll.DataToSketchUDAF
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- All Implemented Interfaces:
org.apache.hadoop.hive.ql.udf.generic.GenericUDAFResolver,org.apache.hadoop.hive.ql.udf.generic.GenericUDAFResolver2
public class DataToSketchUDAF extends org.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolverHive UDAF to create an HllSketch from raw data.Note Strings as raw data values are encoded as a UTF-16 VARCHAR prior to being submitted to the sketch. If the user requires a different encoding for cross-platform compatibility, it is recommended that these values be encoded prior to being submitted and then typed as a BINARY byte[].
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Nested Class Summary
Nested Classes Modifier and Type Class Description static classDataToSketchUDAF.DataToSketchEvaluator
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Constructor Summary
Constructors Constructor Description DataToSketchUDAF()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluatorgetEvaluator(org.apache.hadoop.hive.ql.udf.generic.GenericUDAFParameterInfo info)Performs argument number and type validation.
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Method Detail
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getEvaluator
public org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator getEvaluator(org.apache.hadoop.hive.ql.udf.generic.GenericUDAFParameterInfo info) throws org.apache.hadoop.hive.ql.parse.SemanticExceptionPerforms argument number and type validation. DataToSketch expects to receive between one and three arguments.- The first (required) is the value to add to the sketch and must be a primitive.
- The second (optional) is the lgK from 4 to 21 (default 12). This must be an integral value and must be constant.
- The third (optional) is the target HLL type and must be a string 'HLL_4', 'HLL_6' or 'HLL_8' (default 'HLL_4').
- Specified by:
getEvaluatorin interfaceorg.apache.hadoop.hive.ql.udf.generic.GenericUDAFResolver2- Overrides:
getEvaluatorin classorg.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolver- Parameters:
info- Parameter info to validate- Returns:
- The GenericUDAFEvaluator that should be used to calculate the function.
- Throws:
org.apache.hadoop.hive.ql.parse.SemanticException- See Also:
#getEvaluator(org.apache.hadoop.hive.ql.udf.generic.GenericUDAFParameterInfo)
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