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/*
* Copyright 2016, Yahoo! Inc.
* Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms.
*/
package com.yahoo.sketches.hive.theta;
import static com.yahoo.sketches.Util.DEFAULT_NOMINAL_ENTRIES;
import static com.yahoo.sketches.Util.DEFAULT_UPDATE_SEED;
import java.util.Arrays;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolver;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFParameterInfo;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector.PrimitiveCategory;
import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils;
@Description(
name = "dataToSketch",
value = "_FUNC_(expr, size, prob, seed) - "
+ "Compute a sketch of given size, sampling probability and seed on data 'expr'",
extended = "Example:\n"
+ "> SELECT dataToSketch(val, 16384) FROM src;\n"
+ "The return value is a binary blob that can be operated on by other sketch related functions."
+ " The sketch size is optional, must be a power of 2 and "
+ "controls the relative error expected from the sketch."
+ " A size of 16384 can be expected to yield errors of roughly +-1.5% in the estimation of uniques."
+ " The default size is defined in the sketches-core library "
+ "and at the time of this writing was 4096 (about 3% error)."
+ " The sampling probability is optional and must be from 0 to 1. The default is 1 (no sampling)"
+ " The seed is optional, and using it is not recommended unless you really know why you need it")
public class DataToSketchUDAF extends AbstractGenericUDAFResolver {
/**
* Performs argument number and type validation. DataToSketch expects
* to receive between one and four arguments.
*
*
The first (required) is the value to add to the sketch and must be a primitive.
*
*
The second (optional) is the sketch size to use. This must be an integral value
* and must be constant.
*
*
The third (optional) is the sampling probability and is a floating point value between
* 0.0 and 1.0. It must be a constant
*
*
The fourth (optional) is an update seed.
* It must be an integral value and must be constant.
*
*
* @see org.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolver
* #getEvaluator(org.apache.hadoop.hive.ql.udf.generic.GenericUDAFParameterInfo)
*
* @param info Parameter info to validate
* @return The GenericUDAFEvaluator that should be used to calculate the function.
*/
@Override
public GenericUDAFEvaluator getEvaluator(final GenericUDAFParameterInfo info) throws SemanticException {
final ObjectInspector[] parameters = info.getParameterObjectInspectors();
// Validate the correct number of parameters
if (parameters.length < 1) {
throw new UDFArgumentException("Please specify at least 1 argument");
}
if (parameters.length > 4) {
throw new UDFArgumentException("Please specify no more than 4 arguments");
}
// Validate first parameter type
ObjectInspectorValidator.validateCategoryPrimitive(parameters[0], 0);
// Validate second argument if present
if (parameters.length > 1) {
ObjectInspectorValidator.validateIntegralParameter(parameters[1], 1);
if (!ObjectInspectorUtils.isConstantObjectInspector(parameters[1])) {
throw new UDFArgumentTypeException(1, "The second argument must be a constant");
}
}
// Validate third argument if present
if (parameters.length > 2) {
ObjectInspectorValidator.validateFloatingPointParameter(parameters[2], 2);
if (!ObjectInspectorUtils.isConstantObjectInspector(parameters[2])) {
throw new UDFArgumentTypeException(2, "The third argument must be a constant");
}
}
// Validate fourth argument if present
if (parameters.length > 3) {
ObjectInspectorValidator.validateIntegralParameter(parameters[3], 3);
if (!ObjectInspectorUtils.isConstantObjectInspector(parameters[3])) {
throw new UDFArgumentTypeException(3, "The fourth argument must be a constant");
}
}
return new DataToSketchEvaluator();
}
public static class DataToSketchEvaluator extends UnionEvaluator {
// FOR PARTIAL1 and COMPLETE modes: ObjectInspectors for original data
private transient PrimitiveObjectInspector samplingProbabilityObjectInspector;
/*
* (non-Javadoc)
*
* @see
* org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator#init(org.apache
* .hadoop.hive.ql.udf.generic.GenericUDAFEvaluator.Mode,
* org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector[])
*/
@Override
public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
super.init(mode, parameters);
if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
// input is original data
inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
if (parameters.length > 1) {
nominalEntriesObjectInspector = (PrimitiveObjectInspector) parameters[1];
}
if (parameters.length > 2) {
samplingProbabilityObjectInspector = (PrimitiveObjectInspector) parameters[2];
}
if (parameters.length > 3) {
seedObjectInspector = (PrimitiveObjectInspector) parameters[3];
}
} else {
// input for PARTIAL2 and FINAL is the output from PARTIAL1
intermediateObjectInspector = (StructObjectInspector) parameters[0];
}
if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
// intermediate results need to include the the nominal number of entries and the seed
return ObjectInspectorFactory.getStandardStructObjectInspector(
Arrays.asList(NOMINAL_ENTRIES_FIELD, SEED_FIELD, SKETCH_FIELD),
Arrays.asList(
PrimitiveObjectInspectorFactory.getPrimitiveWritableObjectInspector(PrimitiveCategory.INT),
PrimitiveObjectInspectorFactory.getPrimitiveWritableObjectInspector(PrimitiveCategory.LONG),
PrimitiveObjectInspectorFactory.getPrimitiveWritableObjectInspector(PrimitiveCategory.BINARY)
)
);
}
// final results include just the sketch
return PrimitiveObjectInspectorFactory.getPrimitiveWritableObjectInspector(PrimitiveCategory.BINARY);
}
/*
* (non-Javadoc)
*
* @see
* org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator#iterate(org
* .apache
* .hadoop.hive.ql.udf.generic.GenericUDAFEvaluator.AggregationBuffer,
* java.lang.Object[])
*/
@Override
public void iterate(final @SuppressWarnings("deprecation") AggregationBuffer agg,
final Object[] parameters) throws HiveException {
if (parameters[0] == null) { return; }
final UnionState state = (UnionState) agg;
if (!state.isInitialized()) {
initializeState(state, parameters);
}
state.update(parameters[0], inputObjectInspector);
}
private void initializeState(final UnionState state, final Object[] parameters) {
int sketchSize = DEFAULT_NOMINAL_ENTRIES;
if (nominalEntriesObjectInspector != null) {
sketchSize = PrimitiveObjectInspectorUtils.getInt(parameters[1], nominalEntriesObjectInspector);
}
float samplingProbability = UnionState.DEFAULT_SAMPLING_PROBABILITY;
if (samplingProbabilityObjectInspector != null) {
samplingProbability = PrimitiveObjectInspectorUtils.getFloat(parameters[2],
samplingProbabilityObjectInspector);
}
long seed = DEFAULT_UPDATE_SEED;
if (seedObjectInspector != null) {
seed = PrimitiveObjectInspectorUtils.getLong(parameters[3], seedObjectInspector);
}
state.init(sketchSize, samplingProbability, seed);
}
}
}
