ENH: right and full outer join for Bloom filter strategy

crunch-core/src/it/java/org/apache/crunch/lib/join/BloomFilterFullOuterJoinIT.java

@@ -0,0 +1,49 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.crunch.lib.join;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+
+public class BloomFilterFullOuterJoinIT extends AbstractFullOuterJoinIT {
+
+  private static String saveTempDir;
+
+  @BeforeClass
+  public static void setUpClass(){
+
+    // Ensure a consistent temporary directory for use of the DistributedCache.
+
+    // The DistributedCache technically isn't supported when running in local mode, and the default
+    // temporary directiory "/tmp" is used as its location. This typically only causes an issue when 
+    // running integration tests on Mac OS X, as OS X doesn't use "/tmp" as it's default temporary
+    // directory. The following call ensures that "/tmp" is used as the temporary directory on all platforms.
+    saveTempDir = System.setProperty("java.io.tmpdir", "/tmp");
+  }
+
+  @AfterClass
+  public static void tearDownClass(){
+    System.setProperty("java.io.tmpdir", saveTempDir);
+  }
+
+  @Override
+  protected <K, U, V> JoinStrategy<K, U, V> getJoinStrategy() {
+    return new BloomFilterJoinStrategy<K, U, V>(20000);
+  }
+
+}

crunch-core/src/it/java/org/apache/crunch/lib/join/BloomFilterRightOuterJoinIT.java

@@ -0,0 +1,49 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.crunch.lib.join;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+
+public class BloomFilterRightOuterJoinIT extends AbstractRightOuterJoinIT {
+
+  private static String saveTempDir;
+
+  @BeforeClass
+  public static void setUpClass(){
+
+    // Ensure a consistent temporary directory for use of the DistributedCache.
+
+    // The DistributedCache technically isn't supported when running in local mode, and the default
+    // temporary directiory "/tmp" is used as its location. This typically only causes an issue when 
+    // running integration tests on Mac OS X, as OS X doesn't use "/tmp" as it's default temporary
+    // directory. The following call ensures that "/tmp" is used as the temporary directory on all platforms.
+    saveTempDir = System.setProperty("java.io.tmpdir", "/tmp");
+  }
+
+  @AfterClass
+  public static void tearDownClass(){
+    System.setProperty("java.io.tmpdir", saveTempDir);
+  }
+
+  @Override
+  protected <K, U, V> JoinStrategy<K, U, V> getJoinStrategy() {
+    return new BloomFilterJoinStrategy<K, U, V>(20000);
+  }
+
+}

crunch-core/src/main/java/org/apache/crunch/fn/ExtractKeyFn.java

@@ -23,8 +23,9 @@
 import org.apache.hadoop.mapreduce.TaskInputOutputContext;
 
 /**
- * Wrapper function for converting a {@code MapFn} into a key-value pair that is
- * used to convert from a {@code PCollection<V>} to a {@code PTable<K, V>}.
+ * Wrapper function for converting a key-from-value extractor {@code MapFn<V, K>} into a
+ * key-value pair extractor that is used to convert from a {@code PCollection<V>} to a
+ * {@code PTable<K, V>}.
  */
 public class ExtractKeyFn<K, V> extends MapFn<V, Pair<K, V>> {
 

crunch-core/src/main/java/org/apache/crunch/fn/IdentityFn.java

@@ -28,8 +28,7 @@ public static <T> IdentityFn<T> getInstance() {
     return (IdentityFn<T>) INSTANCE;
   }
 
-  // Non-instantiable
-  private IdentityFn() {
+  protected IdentityFn() {
   }
 
   @Override

crunch-core/src/main/java/org/apache/crunch/lib/join/BloomFilterJoinStrategy.java

@@ -33,6 +33,9 @@
 import org.apache.crunch.Pair;
 import org.apache.crunch.ParallelDoOptions;
 import org.apache.crunch.ReadableData;
+import org.apache.crunch.fn.ExtractKeyFn;
+import org.apache.crunch.fn.FilterFns;
+import org.apache.crunch.fn.IdentityFn;
 import org.apache.crunch.types.PType;
 import org.apache.crunch.types.PTypeFamily;
 import org.apache.crunch.types.avro.AvroMode;
@@ -57,6 +60,10 @@
  * This strategy is useful in cases where the right-side table contains many keys that are not
  * present in the left-side table. In this case, the use of the Bloom filter avoids a
  * potentially costly shuffle phase for data that would never be joined to the left side.
+ * <p>
+ * Implementation Note: right and full outer join type are handled by splitting the right-side
+ * table (the bigger one) into two disjunctive streams: negatively filtered (right outer part)
+ * and positively filtered (passed to delegate strategy).
  */
 public class BloomFilterJoinStrategy<K, U, V> implements JoinStrategy<K, U, V> {
 
@@ -120,30 +127,42 @@ private static int getOptimalNumHash(int numElements, float vectorSize) {
   @Override
   public PTable<K, Pair<U, V>> join(PTable<K, U> left, PTable<K, V> right, JoinType joinType) {
 
-    if (joinType != JoinType.INNER_JOIN && joinType != JoinType.LEFT_OUTER_JOIN) {
-      throw new IllegalStateException("JoinType " + joinType + " is not supported for BloomFilter joins");
-    }
-
-    PTable<K,V> filteredRightSide;
     PType<BloomFilter> bloomFilterType = getBloomFilterType(left.getTypeFamily());
     PCollection<BloomFilter> bloomFilters = left.keys().parallelDo(
         "Create bloom filters",
-        new CreateBloomFilterFn(vectorSize, nbHash, left.getKeyType()),
+        new CreateBloomFilterFn<>(vectorSize, nbHash, left.getKeyType()),
         bloomFilterType);
 
     ReadableData<BloomFilter> bloomData = bloomFilters.asReadable(true);
-    FilterKeysWithBloomFilterFn<K, V> filterKeysFn = new FilterKeysWithBloomFilterFn<K, V>(
-        bloomData,
-        vectorSize, nbHash,
-        left.getKeyType());
+    FilterKeysWithBloomFilterFn<K, V> filterKeysFn = new FilterKeysWithBloomFilterFn<>(
+        bloomData, vectorSize, nbHash, left.getKeyType());
+
+    if (joinType != JoinType.INNER_JOIN && joinType != JoinType.LEFT_OUTER_JOIN) {
+      right = right.parallelDo(
+          "disable deep copy", new DeepCopyDisablerFn<Pair<K, V>>(), right.getPTableType());
+    }
 
-    ParallelDoOptions.Builder optionsBuilder = ParallelDoOptions.builder();
-    optionsBuilder.sourceTargets(bloomData.getSourceTargets());
+    ParallelDoOptions options = ParallelDoOptions.builder()
+        .sourceTargets(bloomData.getSourceTargets()).build();
+    PTable<K, V> filteredRightSide = right.parallelDo(
+        "Filter right-side with BloomFilters",
+        filterKeysFn, right.getPTableType(), options);
 
-    filteredRightSide = right.parallelDo("Filter right side with BloomFilters",
-        filterKeysFn, right.getPTableType(), optionsBuilder.build());
+    PTable<K, Pair<U, V>> leftJoinedWithFilteredRight = delegateJoinStrategy
+        .join(left, filteredRightSide, joinType);
 
-    return delegateJoinStrategy.join(left, filteredRightSide, joinType);
+    if (joinType == JoinType.INNER_JOIN || joinType == JoinType.LEFT_OUTER_JOIN) {
+      return leftJoinedWithFilteredRight;
+    }
+
+    return leftJoinedWithFilteredRight.union(
+        right
+            .parallelDo(
+                "Negatively filter right-side with BloomFilters",
+                FilterFns.not(filterKeysFn), right.getPTableType(), options)
+            .mapValues(
+                "Right outer join: attach null as left-value",
+                new NullKeyFn<U, V>(), leftJoinedWithFilteredRight.getValueType()));
   }
 
   /**
@@ -324,4 +343,36 @@ public byte[] map(T input) {
 
   }
 
+  /**
+   * Converts value into a null-value pair. It is used to convert negatively filtered
+   * right-side values into right outer join part.
+   */
+  private static class NullKeyFn<K, V> extends ExtractKeyFn<K, V> {
+    public NullKeyFn() {
+      super(new MapFn<V, K>() {
+        @Override public K map(V input) {
+          return null;
+        }
+
+        @Override public float scaleFactor() {
+          return 0.0001f;
+        }
+      });
+    }
+  }
+
+  /**
+   * Right and full outer join types are handled by splitting the right-side table (the bigger one)
+   * into two disjunctive streams: negatively filtered (right outer part) and positively filtered.
+   * To prevent concurrent modification Crunch performs a deep copy of such a splitted stream by
+   * default (see {@link DoFn#disableDeepCopy()}), which introduces an extra overhead. Since Bloom
+   * Filter directs every record to exactly one of these streams, making concurrent modification
+   * impossible, we can safely disable this feature. To achieve this we put the {@code right} PTable
+   * through a {@code parallelDo} call with this {@code DoFn}.
+   */
+  private static class DeepCopyDisablerFn<T> extends IdentityFn<T> {
+    @Override public boolean disableDeepCopy() {
+      return true;
+    }
+  }
 }