/*
* 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.pig.builtin;
import java.io.IOException;
import org.apache.pig.Algebraic;
import org.apache.pig.EvalFunc;
import org.apache.pig.JVMReuseManager;
import org.apache.pig.PigConfiguration;
import org.apache.pig.StaticDataCleanup;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce;
import org.apache.pig.data.BagFactory;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.InternalDistinctBag;
import org.apache.pig.data.SingleTupleBag;
import org.apache.pig.data.Tuple;
import org.apache.pig.data.TupleFactory;
/**
* Find the distinct set of tuples in a bag.
* This is a blocking operator. All the input is put in the hashset implemented
* in DistinctDataBag which also provides the other DataBag interfaces.
*/
public class Distinct extends EvalFunc<DataBag> implements Algebraic {
private static TupleFactory tupleFactory = TupleFactory.getInstance();
private static boolean initialized = false;
private static boolean useDefaultBag = false;
static {
JVMReuseManager.getInstance().registerForStaticDataCleanup(Distinct.class);
}
@StaticDataCleanup
public static void staticDataCleanup() {
initialized = false;
useDefaultBag = false;
}
@Override
public DataBag exec(Tuple input) throws IOException {
return getDistinct(input);
}
@Override
public String getFinal() {
return Final.class.getName();
}
@Override
public String getInitial() {
return Initial.class.getName();
}
@Override
public String getIntermed() {
return Intermediate.class.getName();
}
static public class Initial extends EvalFunc<Tuple> {
@Override
public Tuple exec(Tuple input) throws IOException {
// the input has a single field which is a tuple
// representing the data we want to distinct.
// unwrap, put in a bag and send down
try {
Tuple single = (Tuple)input.get(0);
DataBag bag = single == null ? createDataBag() : new SingleTupleBag(single);
return tupleFactory.newTuple(bag);
} catch (ExecException e) {
throw e;
}
}
}
static public class Intermediate extends EvalFunc<Tuple> {
@Override
public Tuple exec(Tuple input) throws IOException {
return tupleFactory.newTuple(getDistinctFromNestedBags(input, this));
}
}
static public class Final extends EvalFunc<DataBag> {
@Override
public DataBag exec(Tuple input) throws IOException {
return getDistinctFromNestedBags(input, this);
}
}
private static DataBag createDataBag() {
if (!initialized) {
initialized = true;
if (PigMapReduce.sJobConfInternal.get() != null) {
String bagType = PigMapReduce.sJobConfInternal.get().get(PigConfiguration.PIG_CACHEDBAG_DISTINCT_TYPE);
if (bagType != null && bagType.equalsIgnoreCase("default")) {
useDefaultBag = true;
}
}
}
// by default, we create InternalDistinctBag, unless user configures
// explicitly to use old bag
return useDefaultBag ? BagFactory.getInstance().newDistinctBag() : new InternalDistinctBag(3);
}
static private DataBag getDistinctFromNestedBags(Tuple input, EvalFunc evalFunc) throws IOException {
DataBag result = createDataBag();
long progressCounter = 0;
try {
DataBag bg = (DataBag)input.get(0);
if (bg == null) {
return result;
}
for (Tuple tuple : bg) {
// Each tuple has a single column
// which is a bag. Get tuples out of it
// and distinct over all tuples
for (Tuple t : (DataBag)tuple.get(0)) {
result.add(t);
++progressCounter;
if((progressCounter % 1000) == 0){
evalFunc.progress();
}
}
}
} catch (ExecException e) {
throw e;
}
return result;
}
protected DataBag getDistinct(Tuple input) throws IOException {
try {
DataBag inputBg = (DataBag)input.get(0);
DataBag result = createDataBag();
if (inputBg == null) {
return result;
}
long progressCounter = 0;
for (Tuple tuple : inputBg) {
result.add(tuple);
++progressCounter;
if ((progressCounter % 1000) == 0) {
progress();
}
}
return result;
} catch (ExecException e) {
throw e;
}
}
}