/*
* 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.backend.hadoop.executionengine.mapReduceLayer;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.log4j.PropertyConfigurator;
import org.apache.pig.PigException;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.HDataType;
import org.apache.pig.backend.hadoop.datastorage.ConfigurationUtil;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.POStatus;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.Result;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POJoinPackage;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POPackage;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POStore;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.util.PlanHelper;
import org.apache.pig.backend.hadoop.executionengine.util.MapRedUtil;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.DataType;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.PigContext;
import org.apache.pig.impl.io.NullablePartitionWritable;
import org.apache.pig.impl.io.NullableTuple;
import org.apache.pig.impl.io.PigNullableWritable;
import org.apache.pig.impl.plan.DependencyOrderWalker;
import org.apache.pig.impl.plan.VisitorException;
import org.apache.pig.impl.util.ObjectSerializer;
import org.apache.pig.impl.util.SpillableMemoryManager;
import org.apache.pig.impl.util.UDFContext;
import org.apache.pig.tools.pigstats.PigStatusReporter;
/**
* This class is the static Mapper & Reducer classes that
* are used by Pig to execute Pig Map Reduce jobs. Since
* there is a reduce phase, the leaf is bound to be a
* POLocalRearrange. So the map phase has to separate the
* key and tuple and collect it into the output
* collector.
*
* The shuffle and sort phase sorts these keys & tuples
* and creates key, List<Tuple> and passes the key and
* iterator to the list. The deserialized POPackage operator
* is used to package the key, List<Tuple> into pigKey,
* Bag<Tuple> where pigKey is of the appropriate pig type and
* then the result of the package is attached to the reduce
* plan which is executed if its not empty. Either the result
* of the reduce plan or the package res is collected into
* the output collector.
*
* The index of the tuple (that is, which bag it should be placed in by the
* package) is packed into the key. This is done so that hadoop sorts the
* keys in order of index for join.
*
*/
public class PigMapReduce {
public static JobContext sJobContext = null;
/**
* @deprecated Use {@link UDFContext} instead in the following way to get
* the job's {@link Configuration}:
* <pre>UdfContext.getUdfContext().getJobConf()</pre>
*/
@Deprecated
public static Configuration sJobConf = null;
public static final ThreadLocal<Configuration> sJobConfInternal = new ThreadLocal<Configuration>();
private final static Tuple DUMMYTUPLE = null;
public static class Map extends PigMapBase {
@Override
public void collect(Context oc, Tuple tuple)
throws InterruptedException, IOException {
Byte index = (Byte)tuple.get(0);
PigNullableWritable key =
HDataType.getWritableComparableTypes(tuple.get(1), keyType);
NullableTuple val = new NullableTuple((Tuple)tuple.get(2));
// Both the key and the value need the index. The key needs it so
// that it can be sorted on the index in addition to the key
// value. The value needs it so that POPackage can properly
// assign the tuple to its slot in the projection.
key.setIndex(index);
val.setIndex(index);
oc.write(key, val);
}
}
/**
* This "specialized" map class is ONLY to be used in pig queries with
* order by a udf. A UDF used for comparison in the order by expects
* to be handed tuples. Hence this map class ensures that the "key" used
* in the order by is wrapped into a tuple (if it isn't already a tuple)
*/
public static class MapWithComparator extends PigMapBase {
@Override
public void collect(Context oc, Tuple tuple)
throws InterruptedException, IOException {
Object keyTuple = null;
if(keyType != DataType.TUPLE) {
Object k = tuple.get(1);
keyTuple = tf.newTuple(k);
} else {
keyTuple = tuple.get(1);
}
Byte index = (Byte)tuple.get(0);
PigNullableWritable key =
HDataType.getWritableComparableTypes(keyTuple, DataType.TUPLE);
NullableTuple val = new NullableTuple((Tuple)tuple.get(2));
// Both the key and the value need the index. The key needs it so
// that it can be sorted on the index in addition to the key
// value. The value needs it so that POPackage can properly
// assign the tuple to its slot in the projection.
key.setIndex(index);
val.setIndex(index);
oc.write(key, val);
}
}
/**
* Used by Skewed Join
*/
public static class MapWithPartitionIndex extends Map {
@Override
public void collect(Context oc, Tuple tuple)
throws InterruptedException, IOException {
Byte tupleKeyIdx = 2;
Byte tupleValIdx = 3;
Byte index = (Byte)tuple.get(0);
Integer partitionIndex = -1;
// for partitioning table, the partition index isn't present
if (tuple.size() == 3) {
//super.collect(oc, tuple);
//return;
tupleKeyIdx--;
tupleValIdx--;
} else {
partitionIndex = (Integer)tuple.get(1);
}
PigNullableWritable key =
HDataType.getWritableComparableTypes(tuple.get(tupleKeyIdx), DataType.TUPLE);
NullablePartitionWritable wrappedKey = new NullablePartitionWritable(key);
NullableTuple val = new NullableTuple((Tuple)tuple.get(tupleValIdx));
// Both the key and the value need the index. The key needs it so
// that it can be sorted on the index in addition to the key
// value. The value needs it so that POPackage can properly
// assign the tuple to its slot in the projection.
wrappedKey.setIndex(index);
// set the partition
wrappedKey.setPartition(partitionIndex);
val.setIndex(index);
oc.write(wrappedKey, val);
}
@Override
protected void runPipeline(PhysicalOperator leaf)
throws IOException, InterruptedException {
while(true){
Result res = leaf.getNext(DUMMYTUPLE);
if(res.returnStatus==POStatus.STATUS_OK){
// For POPartitionRearrange, the result is a bag.
// This operator is used for skewed join
if (res.result instanceof DataBag) {
Iterator<Tuple> its = ((DataBag)res.result).iterator();
while(its.hasNext()) {
collect(outputCollector, its.next());
}
}else{
collect(outputCollector, (Tuple)res.result);
}
continue;
}
if(res.returnStatus==POStatus.STATUS_EOP) {
return;
}
if(res.returnStatus==POStatus.STATUS_NULL) {
continue;
}
if(res.returnStatus==POStatus.STATUS_ERR){
// remember that we had an issue so that in
// close() we can do the right thing
errorInMap = true;
// if there is an errmessage use it
String errMsg;
if(res.result != null) {
errMsg = "Received Error while " +
"processing the map plan: " + res.result;
} else {
errMsg = "Received Error while " +
"processing the map plan.";
}
int errCode = 2055;
throw new ExecException(errMsg, errCode, PigException.BUG);
}
}
}
}
public static class Reduce
extends Reducer <PigNullableWritable, NullableTuple, PigNullableWritable, Writable> {
protected final Log log = LogFactory.getLog(getClass());
//The reduce plan
protected PhysicalPlan rp;
// Store operators
protected List<POStore> stores;
//The POPackage operator which is the
//root of every Map Reduce plan is
//obtained through the job conf. The portion
//remaining after its removal is the reduce
//plan
protected POPackage pack;
ProgressableReporter pigReporter;
protected Context outputCollector;
protected boolean errorInReduce = false;
PhysicalOperator[] roots;
private PhysicalOperator leaf;
PigContext pigContext = null;
protected volatile boolean initialized = false;
/**
* Configures the Reduce plan, the POPackage operator
* and the reporter thread
*/
@SuppressWarnings("unchecked")
@Override
protected void setup(Context context) throws IOException, InterruptedException {
super.setup(context);
Configuration jConf = context.getConfiguration();
SpillableMemoryManager.configure(ConfigurationUtil.toProperties(jConf));
sJobContext = context;
sJobConfInternal.set(context.getConfiguration());
sJobConf = context.getConfiguration();
try {
PigContext.setPackageImportList((ArrayList<String>)ObjectSerializer.deserialize(jConf.get("udf.import.list")));
pigContext = (PigContext)ObjectSerializer.deserialize(jConf.get("pig.pigContext"));
rp = (PhysicalPlan) ObjectSerializer.deserialize(jConf
.get("pig.reducePlan"));
stores = PlanHelper.getStores(rp);
pack = (POPackage)ObjectSerializer.deserialize(jConf.get("pig.reduce.package"));
// To be removed
if(rp.isEmpty())
log.debug("Reduce Plan empty!");
else{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
rp.explain(baos);
log.debug(baos.toString());
}
pigReporter = new ProgressableReporter();
if(!(rp.isEmpty())) {
roots = rp.getRoots().toArray(new PhysicalOperator[1]);
leaf = rp.getLeaves().get(0);
}
// Get the UDF specific context
MapRedUtil.setupUDFContext(jConf);
} catch (IOException ioe) {
String msg = "Problem while configuring reduce plan.";
throw new RuntimeException(msg, ioe);
}
}
/**
* The reduce function which packages the key and List<Tuple>
* into key, Bag<Tuple> after converting Hadoop type key into Pig type.
* The package result is either collected as is, if the reduce plan is
* empty or after passing through the reduce plan.
*/
@Override
protected void reduce(PigNullableWritable key, Iterable<NullableTuple> tupIter, Context context)
throws IOException, InterruptedException {
if (!initialized) {
initialized = true;
// cache the collector for use in runPipeline()
// which could additionally be called from close()
this.outputCollector = context;
pigReporter.setRep(context);
PhysicalOperator.setReporter(pigReporter);
boolean aggregateWarning = "true".equalsIgnoreCase(pigContext.getProperties().getProperty("aggregate.warning"));
PigHadoopLogger pigHadoopLogger = PigHadoopLogger.getInstance();
pigHadoopLogger.setAggregate(aggregateWarning);
PigStatusReporter.setContext(context);
pigHadoopLogger.setReporter(PigStatusReporter.getInstance());
PhysicalOperator.setPigLogger(pigHadoopLogger);
for (POStore store: stores) {
MapReducePOStoreImpl impl
= new MapReducePOStoreImpl(context);
store.setStoreImpl(impl);
store.setUp();
}
}
// In the case we optimize the join, we combine
// POPackage and POForeach - so we could get many
// tuples out of the getnext() call of POJoinPackage
// In this case, we process till we see EOP from
// POJoinPacakage.getNext()
if (pack instanceof POJoinPackage)
{
pack.attachInput(key, tupIter.iterator());
while (true)
{
if (processOnePackageOutput(context))
break;
}
}
else {
// join is not optimized, so package will
// give only one tuple out for the key
pack.attachInput(key, tupIter.iterator());
processOnePackageOutput(context);
}
}
// return: false-more output
// true- end of processing
public boolean processOnePackageOutput(Context oc)
throws IOException, InterruptedException {
Result res = pack.getNext(DUMMYTUPLE);
if(res.returnStatus==POStatus.STATUS_OK){
Tuple packRes = (Tuple)res.result;
if(rp.isEmpty()){
oc.write(null, packRes);
return false;
}
for (int i = 0; i < roots.length; i++) {
roots[i].attachInput(packRes);
}
runPipeline(leaf);
}
if(res.returnStatus==POStatus.STATUS_NULL) {
return false;
}
if(res.returnStatus==POStatus.STATUS_ERR){
int errCode = 2093;
String msg = "Encountered error in package operator while processing group.";
throw new ExecException(msg, errCode, PigException.BUG);
}
if(res.returnStatus==POStatus.STATUS_EOP) {
return true;
}
return false;
}
/**
* @param leaf
* @throws InterruptedException
* @throws IOException
*/
protected void runPipeline(PhysicalOperator leaf)
throws InterruptedException, IOException {
while(true)
{
Result redRes = leaf.getNext(DUMMYTUPLE);
if(redRes.returnStatus==POStatus.STATUS_OK){
try{
outputCollector.write(null, (Tuple)redRes.result);
}catch(Exception e) {
throw new IOException(e);
}
continue;
}
if(redRes.returnStatus==POStatus.STATUS_EOP) {
return;
}
if(redRes.returnStatus==POStatus.STATUS_NULL) {
continue;
}
if(redRes.returnStatus==POStatus.STATUS_ERR){
// remember that we had an issue so that in
// close() we can do the right thing
errorInReduce = true;
// if there is an errmessage use it
String msg;
if(redRes.result != null) {
msg = "Received Error while " +
"processing the reduce plan: " + redRes.result;
} else {
msg = "Received Error while " +
"processing the reduce plan.";
}
int errCode = 2090;
throw new ExecException(msg, errCode, PigException.BUG);
}
}
}
/**
* Will be called once all the intermediate keys and values are
* processed. So right place to stop the reporter thread.
*/
@Override
protected void cleanup(Context context) throws IOException, InterruptedException {
super.cleanup(context);
if(errorInReduce) {
// there was an error in reduce - just return
return;
}
if(PigMapReduce.sJobConfInternal.get().get("pig.stream.in.reduce", "false").equals("true")) {
// If there is a stream in the pipeline we could
// potentially have more to process - so lets
// set the flag stating that all map input has been sent
// already and then lets run the pipeline one more time
// This will result in nothing happening in the case
// where there is no stream in the pipeline
rp.endOfAllInput = true;
runPipeline(leaf);
}
for (POStore store: stores) {
if (!initialized) {
MapReducePOStoreImpl impl
= new MapReducePOStoreImpl(context);
store.setStoreImpl(impl);
store.setUp();
}
store.tearDown();
}
//Calling EvalFunc.finish()
UDFFinishVisitor finisher = new UDFFinishVisitor(rp, new DependencyOrderWalker<PhysicalOperator, PhysicalPlan>(rp));
try {
finisher.visit();
} catch (VisitorException e) {
throw new IOException("Error trying to finish UDFs",e);
}
PhysicalOperator.setReporter(null);
initialized = false;
}
}
/**
* This "specialized" reduce class is ONLY to be used in pig queries with
* order by a udf. A UDF used for comparison in the order by expects
* to be handed tuples. Hence a specialized map class (PigMapReduce.MapWithComparator)
* ensures that the "key" used in the order by is wrapped into a tuple (if it
* isn't already a tuple). This reduce class unwraps this tuple in the case where
* the map had wrapped into a tuple and handes the "unwrapped" key to the POPackage
* for processing
*/
public static class ReduceWithComparator extends PigMapReduce.Reduce {
private byte keyType;
/**
* Configures the Reduce plan, the POPackage operator
* and the reporter thread
*/
@Override
protected void setup(Context context) throws IOException, InterruptedException {
super.setup(context);
keyType = pack.getKeyType();
}
/**
* The reduce function which packages the key and List<Tuple>
* into key, Bag<Tuple> after converting Hadoop type key into Pig type.
* The package result is either collected as is, if the reduce plan is
* empty or after passing through the reduce plan.
*/
@Override
protected void reduce(PigNullableWritable key, Iterable<NullableTuple> tupIter, Context context)
throws IOException, InterruptedException {
if (!initialized) {
initialized = true;
// cache the collector for use in runPipeline()
// which could additionally be called from close()
this.outputCollector = context;
pigReporter.setRep(context);
PhysicalOperator.setReporter(pigReporter);
boolean aggregateWarning = "true".equalsIgnoreCase(pigContext.getProperties().getProperty("aggregate.warning"));
PigHadoopLogger pigHadoopLogger = PigHadoopLogger.getInstance();
pigHadoopLogger.setAggregate(aggregateWarning);
PigStatusReporter.setContext(context);
pigHadoopLogger.setReporter(PigStatusReporter.getInstance());
PhysicalOperator.setPigLogger(pigHadoopLogger);
for (POStore store: stores) {
MapReducePOStoreImpl impl
= new MapReducePOStoreImpl(context);
store.setStoreImpl(impl);
store.setUp();
}
}
// If the keyType is not a tuple, the MapWithComparator.collect()
// would have wrapped the key into a tuple so that the
// comparison UDF used in the order by can process it.
// We need to unwrap the key out of the tuple and hand it
// to the POPackage for processing
if(keyType != DataType.TUPLE) {
Tuple t = (Tuple)(key.getValueAsPigType());
try {
key = HDataType.getWritableComparableTypes(t.get(0), keyType);
} catch (ExecException e) {
throw e;
}
}
pack.attachInput(key, tupIter.iterator());
Result res = pack.getNext(DUMMYTUPLE);
if(res.returnStatus==POStatus.STATUS_OK){
Tuple packRes = (Tuple)res.result;
if(rp.isEmpty()){
context.write(null, packRes);
return;
}
rp.attachInput(packRes);
List<PhysicalOperator> leaves = rp.getLeaves();
PhysicalOperator leaf = leaves.get(0);
runPipeline(leaf);
}
if(res.returnStatus==POStatus.STATUS_NULL) {
return;
}
if(res.returnStatus==POStatus.STATUS_ERR){
int errCode = 2093;
String msg = "Encountered error in package operator while processing group.";
throw new ExecException(msg, errCode, PigException.BUG);
}
}
}
}