Merge pull request #43 from DataSketches/hll-udfs

HLL sketch UDFs

src/main/java/com/yahoo/sketches/pig/hll/AlgebraicFinal.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2017, 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.pig.hll;
+
+import java.io.IOException;
+
+import org.apache.log4j.Logger;
+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.Tuple;
+
+import com.yahoo.memory.Memory;
+import com.yahoo.sketches.hll.HllSketch;
+import com.yahoo.sketches.hll.TgtHllType;
+import com.yahoo.sketches.hll.Union;
+
+/**
+ * Class used to calculate the final pass of an <i>Algebraic</i> sketch
+ * operation. It will receive a bag of values returned by either the <i>Intermediate</i>
+ * stage or the <i>Initial</i> stages, so it needs to be able to differentiate between and
+ * interpret both types.
+ * 
+ * @author Alexander Saydakov
+ */
+abstract class AlgebraicFinal extends EvalFunc<DataByteArray> {
+
+  private final int lgK_;
+  private final TgtHllType tgtHllType_;
+  private DataByteArray emptySketch_; // this is to cash an empty sketch tuple
+  private boolean isFirstCall_ = true; // for logging
+
+  /**
+   * Constructor with primitives for the final passes of an Algebraic function.
+   *
+   * @param lgK parameter controlling the sketch size and accuracy
+   * @param tgtHllType HLL type of the resulting sketch
+   */
+  public AlgebraicFinal(final int lgK, final TgtHllType tgtHllType) {
+    lgK_ = lgK;
+    tgtHllType_ = tgtHllType;
+  }
+
+  @Override
+  public DataByteArray exec(final Tuple inputTuple) throws IOException {
+    if (isFirstCall_) {
+      Logger.getLogger(getClass()).info("Algebraic was used");
+      isFirstCall_ = false;
+    }
+    if (inputTuple == null || inputTuple.size() == 0) {
+      return getEmptySketch();
+    }
+    final Union union = new Union(lgK_);
+    final DataBag outerBag = (DataBag) inputTuple.get(0);
+    if (outerBag == null) {
+      return getEmptySketch();
+    }
+    for (final Tuple dataTuple: outerBag) {
+      final Object f0 = dataTuple.get(0); // inputTuple.bag0.dataTupleN.f0
+      if (f0 == null) {
+        continue;
+      }
+      if (f0 instanceof DataBag) {
+        final DataBag innerBag = (DataBag) f0; // inputTuple.bag0.dataTupleN.f0:bag
+        if (innerBag.size() == 0) { continue; }
+        // If field 0 of a dataTuple is a Bag, all innerTuples of this inner bag
+        // will be passed into the union.
+        // It is due to system bagged outputs from multiple mapper Initial functions.
+        // The Intermediate stage was bypassed.
+        updateUnion(innerBag, union);
+      } else if (f0 instanceof DataByteArray) { // inputTuple.bag0.dataTupleN.f0:DBA
+        // If field 0 of a dataTuple is a DataByteArray, we assume it is a sketch
+        // due to system bagged outputs from multiple mapper Intermediate functions.
+        // Each dataTuple.DBA:sketch will merged into the union.
+        final DataByteArray dba = (DataByteArray) f0;
+        union.update(HllSketch.heapify(Memory.wrap(dba.get())));
+      } else { // we should never get here
+        throw new IllegalArgumentException("dataTuple.Field0 is not a DataBag or DataByteArray: "
+            + f0.getClass().getName());
+      }
+    }
+    return new DataByteArray(union.getResult(tgtHllType_).toCompactByteArray());
+  }
+
+  abstract void updateUnion(DataBag bag, Union union) throws ExecException;
+
+  private DataByteArray getEmptySketch() {
+    if (emptySketch_ == null) {
+      emptySketch_ = new DataByteArray(
+          new HllSketch(lgK_, tgtHllType_).toCompactByteArray());
+    }
+    return emptySketch_;
+  }
+
+}

src/main/java/com/yahoo/sketches/pig/hll/AlgebraicInitial.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2017, 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.pig.hll;
+
+import java.io.IOException;
+
+import org.apache.log4j.Logger;
+import org.apache.pig.EvalFunc;
+import org.apache.pig.data.Tuple;
+
+/**
+ * Class used to calculate the initial pass of an Algebraic sketch operation.
+ *
+ * <p>The Initial class simply passes through all records unchanged so that they can be
+ * processed by the intermediate processor instead.
+ * 
+ * @author Alexander Saydakov
+ */
+public class AlgebraicInitial extends EvalFunc<Tuple> {
+
+  private boolean isFirstCall_ = true;
+
+  /**
+   * Default constructor for the initial pass of an Algebraic function.
+   */
+  public AlgebraicInitial() {}
+
+  /**
+   * Constructor for the initial pass of an Algebraic function. Pig will call this and pass the
+   * same constructor arguments as the original UDF. In this case the arguments are ignored.
+   *
+   * @param lgK in a form of a String
+   */
+  public AlgebraicInitial(final String lgK) {}
+
+  /**
+   * Constructor for the initial pass of an Algebraic function. Pig will call this and pass the
+   * same constructor arguments as the original UDF. In this case the arguments are ignored.
+   *
+   * @param lgK in a form of a String
+   * @param tgtHllType in a form of a String
+   */
+  public AlgebraicInitial(final String lgK, final String tgtHllType) {}
+
+  @Override
+  public Tuple exec(final Tuple inputTuple) throws IOException {
+    if (isFirstCall_) {
+      Logger.getLogger(getClass()).info("Algebraic was used");
+      isFirstCall_ = false;
+    }
+    return inputTuple;
+  }
+
+}

src/main/java/com/yahoo/sketches/pig/hll/AlgebraicIntermediate.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2017, 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.pig.hll;
+
+import java.io.IOException;
+
+import org.apache.log4j.Logger;
+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.Tuple;
+import org.apache.pig.data.TupleFactory;
+
+import com.yahoo.memory.Memory;
+import com.yahoo.sketches.hll.HllSketch;
+import com.yahoo.sketches.hll.TgtHllType;
+import com.yahoo.sketches.hll.Union;
+
+/**
+ * Class used to calculate the intermediate combiner pass of an <i>Algebraic</i> sketch
+ * operation. This is called from the combiner, and may be called multiple times (from a mapper
+ * and from a reducer). It will receive a bag of values returned by either the <i>Intermediate</i>
+ * stage or the <i>Initial</i> stages, so it needs to be able to differentiate between and
+ * interpret both types.
+ * 
+ * @author Alexander Saydakov
+ */
+abstract class AlgebraicIntermediate extends EvalFunc<Tuple> {
+
+  private static final TupleFactory tupleFactory_ = TupleFactory.getInstance();
+
+  private final int lgK_;
+  private final TgtHllType tgtHllType_;
+  private Tuple emptySketchTuple_; // this is to cash an empty sketch tuple
+  private boolean isFirstCall_ = true; // for logging
+
+  /**
+   * Constructor with primitives for the intermediate pass of an Algebraic function.
+   *
+   * @param lgK parameter controlling the sketch size and accuracy
+   * @param tgtHllType HLL type of the resulting sketch
+   */
+  public AlgebraicIntermediate(final int lgK, final TgtHllType tgtHllType) {
+    lgK_ = lgK;
+    tgtHllType_ = tgtHllType;
+  }
+
+  @Override
+  public Tuple exec(final Tuple inputTuple) throws IOException {
+    if (isFirstCall_) {
+      Logger.getLogger(getClass()).info("Algebraic was used");
+      isFirstCall_ = false;
+    }
+    if (inputTuple == null || inputTuple.size() == 0) {
+      return getEmptySketchTuple();
+    }
+    final DataBag outerBag = (DataBag) inputTuple.get(0);
+    if (outerBag == null) {
+      return getEmptySketchTuple();
+    }
+    final Union union = new Union(lgK_);
+    for (final Tuple dataTuple: outerBag) {
+      final Object f0 = dataTuple.get(0); // inputTuple.bag0.dataTupleN.f0
+      if (f0 == null) { continue; }
+      if (f0 instanceof DataBag) {
+        final DataBag innerBag = (DataBag) f0; // inputTuple.bag0.dataTupleN.f0:bag
+        if (innerBag.size() == 0) { continue; }
+        // If field 0 of a dataTuple is a Bag, all innerTuples of this inner bag
+        // will be passed into the union.
+        // It is due to system bagged outputs from multiple mapper Initial functions.
+        // The Intermediate stage was bypassed.
+        updateUnion(innerBag, union);
+      } else if (f0 instanceof DataByteArray) { // inputTuple.bag0.dataTupleN.f0:DBA
+        // If field 0 of a dataTuple is a DataByteArray, we assume it is a sketch
+        // due to system bagged outputs from multiple mapper Intermediate functions.
+        // Each dataTuple.DBA:sketch will merged into the union.
+        final DataByteArray dba = (DataByteArray) f0;
+        union.update(HllSketch.heapify(Memory.wrap(dba.get())));
+      } else { // we should never get here
+        throw new IllegalArgumentException("dataTuple.Field0 is not a DataBag or DataByteArray: "
+            + f0.getClass().getName());
+      }
+    }
+    return tupleFactory_.newTuple(new DataByteArray(union.getResult(tgtHllType_).toCompactByteArray()));
+  }
+
+  abstract void updateUnion(DataBag bag, Union union) throws ExecException;
+
+  private Tuple getEmptySketchTuple() {
+    if (emptySketchTuple_ == null) {
+      emptySketchTuple_ = tupleFactory_.newTuple(new DataByteArray(
+          new HllSketch(lgK_, tgtHllType_).toCompactByteArray()));
+    }
+    return emptySketchTuple_;
+  }
+
+}