/*
* Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.mapreduce.impl.task;
import com.hazelcast.logging.ILogger;
import com.hazelcast.mapreduce.JobPartitionState;
import com.hazelcast.mapreduce.JobProcessInformation;
import com.hazelcast.mapreduce.JobTracker;
import com.hazelcast.mapreduce.Reducer;
import com.hazelcast.mapreduce.impl.AbstractJobTracker;
import com.hazelcast.mapreduce.impl.HashMapAdapter;
import com.hazelcast.mapreduce.impl.MapReduceService;
import com.hazelcast.mapreduce.impl.MapReduceUtil;
import com.hazelcast.mapreduce.impl.notification.IntermediateChunkNotification;
import com.hazelcast.mapreduce.impl.notification.LastChunkNotification;
import com.hazelcast.mapreduce.impl.notification.MapReduceNotification;
import com.hazelcast.mapreduce.impl.notification.ReducingFinishedNotification;
import com.hazelcast.mapreduce.impl.operation.CancelJobSupervisorOperation;
import com.hazelcast.mapreduce.impl.operation.GetResultOperationFactory;
import com.hazelcast.mapreduce.impl.operation.RequestPartitionProcessed;
import com.hazelcast.mapreduce.impl.operation.RequestPartitionResult;
import com.hazelcast.nio.Address;
import com.hazelcast.spi.NodeEngine;
import com.hazelcast.util.ExceptionUtil;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.atomic.AtomicReference;
import static com.hazelcast.mapreduce.JobPartitionState.State.REDUCING;
import static com.hazelcast.mapreduce.impl.MapReduceUtil.createJobProcessInformation;
import static com.hazelcast.mapreduce.impl.operation.RequestPartitionResult.ResultState.SUCCESSFUL;
/**
* The JobSupervisor is the overall control instance of a map reduce job. There is one JobSupervisor per
* unique name-jobId combination and per cluster member.<br/>
* The emitting cluster member's JobSupervisor has a special control function to synchronize the work of
* the other "worker-members" that only execute the task. This job owner node also assigns reducing members
* to keys and checks for topology changes that hurt the currently running job and enforces the rules set
* by the {@link com.hazelcast.mapreduce.TopologyChangedStrategy} in case of a topology change situation.
*/
public class JobSupervisor {
private final ConcurrentMap<Object, Reducer> reducers = new ConcurrentHashMap<Object, Reducer>();
private final ConcurrentMap<Integer, Set<Address>> remoteReducers = new ConcurrentHashMap<Integer, Set<Address>>();
private final AtomicReference<DefaultContext> context = new AtomicReference<DefaultContext>();
private final ConcurrentMap<Object, Address> keyAssignments = new ConcurrentHashMap<Object, Address>();
private final Address jobOwner;
private final boolean ownerNode;
private final AbstractJobTracker jobTracker;
private final JobTaskConfiguration configuration;
private final MapReduceService mapReduceService;
private final ExecutorService executorService;
private final JobProcessInformationImpl jobProcessInformation;
public JobSupervisor(JobTaskConfiguration configuration, AbstractJobTracker jobTracker, boolean ownerNode,
MapReduceService mapReduceService) {
this.jobTracker = jobTracker;
this.ownerNode = ownerNode;
this.configuration = configuration;
this.mapReduceService = mapReduceService;
this.jobOwner = configuration.getJobOwner();
this.executorService = mapReduceService.getExecutorService(configuration.getName());
// Calculate partition count
this.jobProcessInformation = createJobProcessInformation(configuration, this);
// Preregister reducer task to handle immediate reducing events
String name = configuration.getName();
String jobId = configuration.getJobId();
jobTracker.registerReducerTask(new ReducerTask(name, jobId, this));
}
public MapReduceService getMapReduceService() {
return mapReduceService;
}
public JobTracker getJobTracker() {
return jobTracker;
}
public void startTasks(MappingPhase mappingPhase) {
// Start map-combiner tasks
jobTracker.registerMapCombineTask(new MapCombineTask(configuration, this, mappingPhase));
}
public void onNotification(MapReduceNotification notification) {
if (notification instanceof IntermediateChunkNotification) {
IntermediateChunkNotification icn = (IntermediateChunkNotification) notification;
ReducerTask reducerTask = jobTracker.getReducerTask(icn.getJobId());
reducerTask.processChunk(icn.getChunk());
} else if (notification instanceof LastChunkNotification) {
LastChunkNotification lcn = (LastChunkNotification) notification;
ReducerTask reducerTask = jobTracker.getReducerTask(lcn.getJobId());
reducerTask.processChunk(lcn.getPartitionId(), lcn.getSender(), lcn.getChunk());
} else if (notification instanceof ReducingFinishedNotification) {
ReducingFinishedNotification rfn = (ReducingFinishedNotification) notification;
processReducerFinished(rfn);
}
}
public void notifyRemoteException(Address remoteAddress, Throwable throwable) {
// Cancel all partition states
jobProcessInformation.cancelPartitionState();
// Notify all other nodes about cancellation
Set<Address> addresses = collectRemoteAddresses();
// Now notify all involved members to cancel the job
cancelRemoteOperations(addresses);
// Cancel local job
TrackableJobFuture future = cancel();
if (future != null) {
// Might be already cancelled by another members exception
ExceptionUtil.fixRemoteStackTrace(throwable, Thread.currentThread().getStackTrace(),
"Operation failed on node: " + remoteAddress);
future.setResult(throwable);
}
}
public boolean cancelAndNotify(Exception exception) {
// Cancel all partition states
jobProcessInformation.cancelPartitionState();
// Notify all other nodes about cancellation
Set<Address> addresses = collectRemoteAddresses();
// Now notify all involved members to cancel the job
cancelRemoteOperations(addresses);
// Cancel local job
TrackableJobFuture future = cancel();
if (future != null) {
// Might be already cancelled by another members exception
future.setResult(exception);
}
return true;
}
// TODO Not yet fully supported
public boolean cancelNotifyAndRestart() {
// Cancel all partition states
jobProcessInformation.cancelPartitionState();
// Notify all other nodes about cancellation
Set<Address> addresses = collectRemoteAddresses();
// Now notify all involved members to cancel the job
cancelRemoteOperations(addresses);
// Kill local tasks
String jobId = getConfiguration().getJobId();
MapCombineTask mapCombineTask = jobTracker.unregisterMapCombineTask(jobId);
if (mapCombineTask != null) {
mapCombineTask.cancel();
}
ReducerTask reducerTask = jobTracker.unregisterReducerTask(jobId);
if (reducerTask != null) {
reducerTask.cancel();
}
// Reset local data
jobProcessInformation.resetPartitionState();
reducers.clear();
remoteReducers.clear();
context.set(null);
keyAssignments.clear();
// Restart
// TODO restart with a new KeyValueJob
return true;
}
public TrackableJobFuture cancel() {
String jobId = getConfiguration().getJobId();
TrackableJobFuture future = jobTracker.unregisterTrackableJob(jobId);
MapCombineTask mapCombineTask = jobTracker.unregisterMapCombineTask(jobId);
if (mapCombineTask != null) {
mapCombineTask.cancel();
}
ReducerTask reducerTask = jobTracker.unregisterReducerTask(jobId);
if (reducerTask != null) {
reducerTask.cancel();
}
mapReduceService.destroyJobSupervisor(this);
return future;
}
public Map<Object, Object> getJobResults() {
Map<Object, Object> result;
if (configuration.getReducerFactory() != null) {
int mapSize = MapReduceUtil.mapSize(reducers.size());
result = new HashMapAdapter<Object, Object>(mapSize);
for (Map.Entry<Object, Reducer> entry : reducers.entrySet()) {
result.put(entry.getKey(), entry.getValue().finalizeReduce());
}
} else {
DefaultContext currentContext = context.get();
result = currentContext.finish();
}
return result;
}
public <KeyIn, ValueIn, ValueOut> Reducer<KeyIn, ValueIn, ValueOut> getReducerByKey(Object key) {
Reducer reducer = reducers.get(key);
if (reducer == null && configuration.getReducerFactory() != null) {
reducer = configuration.getReducerFactory().newReducer(key);
Reducer oldReducer = reducers.putIfAbsent(key, reducer);
if (oldReducer != null) {
reducer = oldReducer;
} else {
reducer.beginReduce(key);
}
}
return reducer;
}
public Address getReducerAddressByKey(Object key) {
Address address = keyAssignments.get(key);
if (address != null) {
return address;
}
return null;
}
public Address assignKeyReducerAddress(Object key) {
// Assign new key to a known member
Address address = keyAssignments.get(key);
if (address == null) {
address = mapReduceService.getKeyMember(key);
Address oldAddress = keyAssignments.putIfAbsent(key, address);
if (oldAddress != null) {
address = oldAddress;
}
}
return address;
}
public boolean checkAssignedMembersAvailable() {
return mapReduceService.checkAssignedMembersAvailable(keyAssignments.values());
}
public boolean assignKeyReducerAddress(Object key, Address address) {
Address oldAssignment = keyAssignments.putIfAbsent(key, address);
return oldAssignment == null || oldAssignment.equals(address);
}
public void checkFullyProcessed(JobProcessInformation processInformation) {
if (isOwnerNode()) {
JobPartitionState[] partitionStates = processInformation.getPartitionStates();
for (JobPartitionState partitionState : partitionStates) {
if (partitionState == null || partitionState.getState() != JobPartitionState.State.PROCESSED) {
return;
}
}
String name = configuration.getName();
String jobId = configuration.getJobId();
NodeEngine nodeEngine = configuration.getNodeEngine();
GetResultOperationFactory operationFactory = new GetResultOperationFactory(name, jobId);
try {
List<Map> results = MapReduceUtil.executeOperation(operationFactory, mapReduceService, nodeEngine, true);
boolean reducedResult = configuration.getReducerFactory() != null;
if (results != null) {
Map<Object, Object> mergedResults = new HashMap<Object, Object>();
for (Map<?, ?> map : results) {
for (Map.Entry entry : map.entrySet()) {
collectResults(reducedResult, mergedResults, entry);
}
}
// Get the initial future object to eventually set the result and cleanup
TrackableJobFuture future = jobTracker.unregisterTrackableJob(jobId);
jobTracker.unregisterMapCombineTask(jobId);
jobTracker.unregisterReducerTask(jobId);
mapReduceService.destroyJobSupervisor(this);
future.setResult(mergedResults);
}
} catch (Exception e) {
// Get the initial future object to eventually set the result and cleanup
TrackableJobFuture future = jobTracker.unregisterTrackableJob(jobId);
jobTracker.unregisterMapCombineTask(jobId);
jobTracker.unregisterReducerTask(jobId);
mapReduceService.destroyJobSupervisor(this);
future.setResult(e);
}
}
}
public <K, V> DefaultContext<K, V> getOrCreateContext(MapCombineTask mapCombineTask) {
DefaultContext<K, V> newContext = new DefaultContext<K, V>(configuration.getCombinerFactory(), mapCombineTask);
if (context.compareAndSet(null, newContext)) {
return newContext;
}
return context.get();
}
public void registerReducerEventInterests(int partitionId, Set<Address> remoteReducers) {
Set<Address> addresses = this.remoteReducers.get(partitionId);
if (addresses == null) {
addresses = new CopyOnWriteArraySet<Address>();
Set<Address> oldSet = this.remoteReducers.putIfAbsent(partitionId, addresses);
if (oldSet != null) {
addresses = oldSet;
}
}
addresses.addAll(remoteReducers);
}
public Collection<Address> getReducerEventInterests(int partitionId) {
return this.remoteReducers.get(partitionId);
}
public JobProcessInformationImpl getJobProcessInformation() {
return jobProcessInformation;
}
public Address getJobOwner() {
return jobOwner;
}
public boolean isOwnerNode() {
return ownerNode;
}
public JobTaskConfiguration getConfiguration() {
return configuration;
}
private void collectResults(boolean reducedResult, Map<Object, Object> mergedResults, Map.Entry entry) {
if (reducedResult) {
mergedResults.put(entry.getKey(), entry.getValue());
} else {
List<Object> list = (List) mergedResults.get(entry.getKey());
if (list == null) {
list = new ArrayList<Object>();
mergedResults.put(entry.getKey(), list);
}
for (Object value : (List) entry.getValue()) {
list.add(value);
}
}
}
private Set<Address> collectRemoteAddresses() {
Set<Address> addresses = new HashSet<Address>();
for (Set<Address> remoteReducerAddresses : remoteReducers.values()) {
addAllFilterJobOwner(addresses, remoteReducerAddresses);
}
for (JobPartitionState partitionState : jobProcessInformation.getPartitionStates()) {
if (partitionState != null && partitionState.getOwner() != null) {
if (!partitionState.getOwner().equals(jobOwner)) {
addresses.add(partitionState.getOwner());
}
}
}
return addresses;
}
private void cancelRemoteOperations(Set<Address> addresses) {
String name = getConfiguration().getName();
String jobId = getConfiguration().getJobId();
for (Address address : addresses) {
try {
CancelJobSupervisorOperation operation = new CancelJobSupervisorOperation(name, jobId);
mapReduceService.processRequest(address, operation, name);
} catch (Exception ignore) {
// We can ignore this exception since we just want to cancel the job
// and the member may be crashed or unreachable in some way
ILogger logger = mapReduceService.getNodeEngine().getLogger(JobSupervisor.class);
logger.finest("Remote node may already be down", ignore);
}
}
}
private void processReducerFinished(final ReducingFinishedNotification notification) {
// Just offload it to free the event queue
executorService.submit(new Runnable() {
@Override
public void run() {
processReducerFinished0(notification);
}
});
}
private void addAllFilterJobOwner(Set<Address> target, Set<Address> source) {
for (Address address : source) {
if (jobOwner.equals(address)) {
continue;
}
target.add(address);
}
}
private void processReducerFinished0(ReducingFinishedNotification notification) {
String name = configuration.getName();
String jobId = configuration.getJobId();
int partitionId = notification.getPartitionId();
Address reducerAddress = notification.getAddress();
if (checkPartitionReductionCompleted(partitionId, reducerAddress)) {
try {
RequestPartitionResult result = mapReduceService
.processRequest(jobOwner, new RequestPartitionProcessed(name, jobId, partitionId, REDUCING), name);
if (result.getResultState() != SUCCESSFUL) {
throw new RuntimeException("Could not finalize processing for partitionId " + partitionId);
}
} catch (Throwable t) {
MapReduceUtil.notifyRemoteException(this, t);
if (t instanceof Error) {
ExceptionUtil.sneakyThrow(t);
}
}
}
}
private boolean checkPartitionReductionCompleted(int partitionId, Address reducerAddress) {
Set<Address> remoteAddresses = remoteReducers.get(partitionId);
if (remoteAddresses == null) {
throw new RuntimeException("Reducer for partition " + partitionId + " not registered");
}
remoteAddresses.remove(reducerAddress);
if (remoteAddresses.size() == 0) {
if (remoteReducers.remove(partitionId) != null) {
return true;
}
}
return false;
}
}