| /* |
| * Copyright 2019, Verizon Media. |
| * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms. |
| */ |
| |
| package com.yahoo.sketches.pig.cpc; |
| |
| import static com.yahoo.sketches.Util.DEFAULT_UPDATE_SEED; |
| |
| import java.io.IOException; |
| |
| import org.apache.log4j.Logger; |
| import org.apache.pig.Accumulator; |
| import org.apache.pig.Algebraic; |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.DataByteArray; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.data.Tuple; |
| |
| import com.yahoo.sketches.cpc.CpcSketch; |
| import com.yahoo.sketches.cpc.CpcUnion; |
| |
| /** |
| * This is a Pig UDF that performs the Union operation on CpcSketches. |
| * This class implements both the <i>Accumulator</i> and <i>Algebraic</i> interfaces. |
| * |
| * @author Alexander Saydakov |
| */ |
| public class UnionSketch extends EvalFunc<DataByteArray> implements Accumulator<DataByteArray>, Algebraic { |
| |
| private DataByteArray emptySketch_; // this is to cash an empty sketch |
| |
| private final int lgK_; |
| private final long seed_; |
| private CpcUnion accumUnion_; |
| private boolean isFirstCall_; |
| |
| /** |
| * Constructor with default lgK and target HLL type |
| */ |
| public UnionSketch() { |
| this(CpcSketch.DEFAULT_LG_K, DEFAULT_UPDATE_SEED); |
| } |
| |
| /** |
| * Constructor with given lgK as string and default seed. |
| * |
| * @param lgK in a form of a String |
| */ |
| public UnionSketch(final String lgK) { |
| this(Integer.parseInt(lgK), DEFAULT_UPDATE_SEED); |
| } |
| |
| /** |
| * Constructor with given lgK and seed as strings |
| * |
| * @param lgK in a form of a String |
| * @param seed in a form of a String |
| */ |
| public UnionSketch(final String lgK, final String seed) { |
| this(Integer.parseInt(lgK), Long.parseLong(seed)); |
| } |
| |
| /** |
| * Base constructor. |
| * |
| * @param lgK parameter controlling the sketch size and accuracy |
| * @param seed for the hash function |
| */ |
| public UnionSketch(final int lgK, final long seed) { |
| super(); |
| lgK_ = lgK; |
| seed_ = seed; |
| } |
| |
| /** |
| * Top-level exec function. |
| * This method accepts an input Tuple containing a Bag of one or more inner <b>Sketch Tuples</b> |
| * and returns a single serialized CpcSketch as a DataByteArray. |
| * |
| * <b>Sketch Tuple</b> is a Tuple containing a single DataByteArray (BYTEARRAY in Pig), which |
| * is a serialized HllSketch. |
| * |
| * @param inputTuple A tuple containing a single bag, containing Sketch Tuples. |
| * @return serialized CpcSketch |
| * @see "org.apache.pig.EvalFunc.exec(org.apache.pig.data.Tuple)" |
| * @throws IOException from Pig. |
| */ |
| @Override |
| public DataByteArray exec(final Tuple inputTuple) throws IOException { |
| if (isFirstCall_) { |
| Logger.getLogger(getClass()).info("Exec was used"); |
| isFirstCall_ = false; |
| } |
| if (inputTuple == null || inputTuple.size() == 0) { |
| if (emptySketch_ == null) { |
| emptySketch_ = new DataByteArray(new CpcSketch(lgK_, seed_).toByteArray()); |
| } |
| return emptySketch_; |
| } |
| final CpcUnion union = new CpcUnion(lgK_, seed_); |
| final DataBag bag = (DataBag) inputTuple.get(0); |
| updateUnion(bag, union, seed_); |
| return new DataByteArray(union.getResult().toByteArray()); |
| } |
| |
| /** |
| * An <i>Accumulator</i> version of the standard <i>exec()</i> method. Like <i>exec()</i>, |
| * accumulator is called with a bag of Sketch Tuples. Unlike <i>exec()</i>, it doesn't serialize the |
| * result at the end. Instead, it can be called multiple times, each time with another bag of |
| * Sketch Tuples to be input to the union. |
| * |
| * @param inputTuple A tuple containing a single bag, containing Sketch Tuples. |
| * @see #exec |
| * @see "org.apache.pig.Accumulator.accumulate(org.apache.pig.data.Tuple)" |
| * @throws IOException by Pig |
| */ |
| @Override |
| public void accumulate(final Tuple inputTuple) throws IOException { |
| if (isFirstCall_) { |
| Logger.getLogger(getClass()).info("Accumulator was used"); |
| isFirstCall_ = false; |
| } |
| if (inputTuple == null || inputTuple.size() == 0) { return; } |
| final DataBag bag = (DataBag) inputTuple.get(0); |
| if (bag == null) { return; } |
| if (accumUnion_ == null) { |
| accumUnion_ = new CpcUnion(lgK_, seed_); |
| } |
| updateUnion(bag, accumUnion_, seed_); |
| } |
| |
| /** |
| * Returns the sketch that has been built up by multiple calls to {@link #accumulate}. |
| * |
| * @return Sketch Tuple. (see {@link #exec} for return tuple format) |
| * @see "org.apache.pig.Accumulator.getValue()" |
| */ |
| @Override |
| public DataByteArray getValue() { |
| if (accumUnion_ == null) { |
| if (emptySketch_ == null) { |
| emptySketch_ = new DataByteArray( |
| new CpcSketch(lgK_, seed_).toByteArray()); |
| } |
| return emptySketch_; |
| } |
| return new DataByteArray(accumUnion_.getResult().toByteArray()); |
| } |
| |
| /** |
| * Cleans up the UDF state after being called using the {@link Accumulator} interface. |
| * |
| * @see "org.apache.pig.Accumulator.cleanup()" |
| */ |
| @Override |
| public void cleanup() { |
| accumUnion_ = null; |
| } |
| |
| @Override |
| public String getInitial() { |
| return AlgebraicInitial.class.getName(); |
| } |
| |
| @Override |
| public String getIntermed() { |
| return UnionSketchAlgebraicIntermediate.class.getName(); |
| } |
| |
| @Override |
| public String getFinal() { |
| return UnionSketchAlgebraicFinal.class.getName(); |
| } |
| |
| static void updateUnion(final DataBag bag, final CpcUnion union, final long seed) throws ExecException { |
| // Bag is not empty. process each innerTuple in the bag |
| for (final Tuple innerTuple : bag) { |
| final Object f0 = innerTuple.get(0); // consider only field 0 |
| if (f0 == null) { |
| continue; |
| } |
| final byte type = innerTuple.getType(0); |
| if (type == DataType.BYTEARRAY) { |
| final DataByteArray dba = (DataByteArray) f0; |
| union.update(CpcSketch.heapify(dba.get(), seed)); |
| } else { |
| throw new IllegalArgumentException("Field type was not DataType.BYTEARRAY: " + type); |
| } |
| } |
| } |
| |
| } |