/*
* 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.cassandra.service;
import java.io.*;
import java.net.InetAddress;
import java.security.MessageDigest;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.Condition;
import com.google.common.base.Objects;
import com.google.common.collect.Sets;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.concurrent.JMXConfigurableThreadPoolExecutor;
import org.apache.cassandra.concurrent.NamedThreadFactory;
import org.apache.cassandra.concurrent.Stage;
import org.apache.cassandra.concurrent.StageManager;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.*;
import org.apache.cassandra.db.compaction.AbstractCompactedRow;
import org.apache.cassandra.db.compaction.CompactionManager;
import org.apache.cassandra.dht.AbstractBounds;
import org.apache.cassandra.dht.RandomPartitioner;
import org.apache.cassandra.dht.Range;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.gms.*;
import org.apache.cassandra.io.IVersionedSerializer;
import org.apache.cassandra.locator.TokenMetadata;
import org.apache.cassandra.net.*;
import org.apache.cassandra.streaming.StreamingRepairTask;
import org.apache.cassandra.utils.*;
/**
* AntiEntropyService encapsulates "validating" (hashing) individual column families,
* exchanging MerkleTrees with remote nodes via a TreeRequest/Response conversation,
* and then triggering repairs for disagreeing ranges.
*
* Every Tree conversation has an 'initiator', where valid trees are sent after generation
* and where the local and remote tree will rendezvous in rendezvous(cf, endpoint, tree).
* Once the trees rendezvous, a Differencer is executed and the service can trigger repairs
* for disagreeing ranges.
*
* Tree comparison and repair triggering occur in the single threaded Stage.ANTIENTROPY.
*
* The steps taken to enact a repair are as follows:
* 1. A major compaction is triggered via nodeprobe:
* * Nodeprobe sends TreeRequest messages to all neighbors of the target node: when a node
* receives a TreeRequest, it will perform a readonly compaction to immediately validate
* the column family.
* 2. The compaction process validates the column family by:
* * Calling Validator.prepare(), which samples the column family to determine key distribution,
* * Calling Validator.add() in order for every row in the column family,
* * Calling Validator.complete() to indicate that all rows have been added.
* * Calling complete() indicates that a valid MerkleTree has been created for the column family.
* * The valid tree is returned to the requesting node via a TreeResponse.
* 3. When a node receives a TreeResponse, it passes the tree to rendezvous(), which checks for trees to
* rendezvous with / compare to:
* * If the tree is local, it is cached, and compared to any trees that were received from neighbors.
* * If the tree is remote, it is immediately compared to a local tree if one is cached. Otherwise,
* the remote tree is stored until a local tree can be generated.
* * A Differencer object is enqueued for each comparison.
* 4. Differencers are executed in Stage.ANTIENTROPY, to compare the two trees, and perform repair via the
* streaming api.
*/
public class AntiEntropyService
{
private static final Logger logger = LoggerFactory.getLogger(AntiEntropyService.class);
// singleton enforcement
public static final AntiEntropyService instance = new AntiEntropyService();
private static final ThreadPoolExecutor executor;
static
{
executor = new JMXConfigurableThreadPoolExecutor(4,
60,
TimeUnit.SECONDS,
new LinkedBlockingQueue<Runnable>(),
new NamedThreadFactory("AntiEntropySessions"),
"internal");
}
public static enum Status
{
STARTED, SESSION_SUCCESS, SESSION_FAILED, FINISHED
}
/**
* A map of active session.
*/
private final ConcurrentMap<String, RepairSession> sessions;
/**
* Protected constructor. Use AntiEntropyService.instance.
*/
protected AntiEntropyService()
{
sessions = new ConcurrentHashMap<String, RepairSession>();
}
/**
* Requests repairs for the given table and column families, and blocks until all repairs have been completed.
*
* @return Future for asynchronous call or null if there is no need to repair
*/
public RepairFuture submitRepairSession(Range<Token> range, String tablename, boolean isSequential, boolean isLocal, String... cfnames)
{
RepairSession session = new RepairSession(range, tablename, isSequential, isLocal, cfnames);
if (session.endpoints.isEmpty())
return null;
RepairFuture futureTask = session.getFuture();
executor.execute(futureTask);
return futureTask;
}
public void terminateSessions()
{
for (RepairSession session : sessions.values())
{
session.forceShutdown();
}
}
// for testing only. Create a session corresponding to a fake request and
// add it to the sessions (avoid NPE in tests)
RepairFuture submitArtificialRepairSession(TreeRequest req, String tablename, String... cfnames)
{
RepairFuture futureTask = new RepairSession(req, tablename, cfnames).getFuture();
executor.execute(futureTask);
return futureTask;
}
/**
* Return all of the neighbors with whom we share the provided range.
*
* @param table table to repair
* @param toRepair token to repair
* @param isLocal need to use only nodes from local datacenter
*
* @return neighbors with whom we share the provided range
*/
static Set<InetAddress> getNeighbors(String table, Range<Token> toRepair, boolean isLocal)
{
StorageService ss = StorageService.instance;
Map<Range<Token>, List<InetAddress>> replicaSets = ss.getRangeToAddressMap(table);
Range<Token> rangeSuperSet = null;
for (Range<Token> range : ss.getLocalRanges(table))
{
if (range.contains(toRepair))
{
rangeSuperSet = range;
break;
}
else if (range.intersects(toRepair))
{
throw new IllegalArgumentException("Requested range intersects a local range but is not fully contained in one; this would lead to imprecise repair");
}
}
if (rangeSuperSet == null || !replicaSets.containsKey(rangeSuperSet))
return Collections.emptySet();
Set<InetAddress> neighbors = new HashSet<InetAddress>(replicaSets.get(rangeSuperSet));
neighbors.remove(FBUtilities.getBroadcastAddress());
if (isLocal)
{
TokenMetadata.Topology topology = ss.getTokenMetadata().cloneOnlyTokenMap().getTopology();
Set<InetAddress> localEndpoints = Sets.newHashSet(topology.getDatacenterEndpoints().get(DatabaseDescriptor.getLocalDataCenter()));
return Sets.intersection(neighbors, localEndpoints);
}
return neighbors;
}
/**
* Register a tree for the given request to be compared to the appropriate trees in Stage.ANTIENTROPY when they become available.
*/
private void rendezvous(TreeRequest request, MerkleTree tree)
{
RepairSession session = sessions.get(request.sessionid);
if (session == null)
{
logger.warn("Got a merkle tree response for unknown repair session {}: either this node has been restarted since the session was started, or the session has been interrupted for an unknown reason. ", request.sessionid);
return;
}
RepairSession.RepairJob job = session.jobs.peek();
if (job == null)
{
assert session.terminated();
return;
}
logger.info(String.format("[repair #%s] Received merkle tree for %s from %s", session.getName(), request.cf.right, request.endpoint));
if (job.addTree(request, tree) == 0)
{
logger.debug("All trees received for " + session.getName() + "/" + request.cf.right);
job.submitDifferencers();
// This job is complete, switching to next in line (note that only
// one thread will can ever do this)
session.jobs.poll();
RepairSession.RepairJob nextJob = session.jobs.peek();
if (nextJob == null)
// We are done with this repair session as far as differencing
// is considern. Just inform the session
session.differencingDone.signalAll();
else
nextJob.sendTreeRequests();
}
}
/**
* Responds to the node that requested the given valid tree.
* @param validator A locally generated validator
* @param local localhost (parameterized for testing)
*/
void respond(Validator validator, InetAddress local)
{
MessagingService ms = MessagingService.instance();
try
{
if (!validator.request.endpoint.equals(FBUtilities.getBroadcastAddress()))
logger.info(String.format("[repair #%s] Sending completed merkle tree to %s for %s", validator.request.sessionid, validator.request.endpoint, validator.request.cf));
ms.sendOneWay(validator.createMessage(), validator.request.endpoint);
}
catch (Exception e)
{
logger.error(String.format("[repair #%s] Error sending completed merkle tree to %s for %s ", validator.request.sessionid, validator.request.endpoint, validator.request.cf), e);
}
}
/**
* A Strategy to handle building and validating a merkle tree for a column family.
*
* Lifecycle:
* 1. prepare() - Initialize tree with samples.
* 2. add() - 0 or more times, to add hashes to the tree.
* 3. complete() - Enqueues any operations that were blocked waiting for a valid tree.
*/
public static class Validator implements Runnable
{
public final TreeRequest request;
public final MerkleTree tree;
// null when all rows with the min token have been consumed
private transient long validated;
private transient MerkleTree.TreeRange range;
private transient MerkleTree.TreeRangeIterator ranges;
private transient DecoratedKey lastKey;
public final static MerkleTree.RowHash EMPTY_ROW = new MerkleTree.RowHash(null, new byte[0]);
public static ValidatorSerializer serializer = new ValidatorSerializer();
public Validator(TreeRequest request)
{
this(request,
// TODO: memory usage (maxsize) should either be tunable per
// CF, globally, or as shared for all CFs in a cluster
new MerkleTree(DatabaseDescriptor.getPartitioner(), request.range, MerkleTree.RECOMMENDED_DEPTH, (int)Math.pow(2, 15)));
}
Validator(TreeRequest request, MerkleTree tree)
{
this.request = request;
this.tree = tree;
// Reestablishing the range because we don't serialize it (for bad
// reason - see MerkleTree for details)
this.tree.fullRange = this.request.range;
validated = 0;
range = null;
ranges = null;
}
public void prepare(ColumnFamilyStore cfs)
{
if (!tree.partitioner().preservesOrder())
{
// You can't beat an even tree distribution for md5
tree.init();
}
else
{
List<DecoratedKey> keys = new ArrayList<DecoratedKey>();
for (DecoratedKey sample : cfs.keySamples(request.range))
{
assert request.range.contains(sample.token): "Token " + sample.token + " is not within range " + request.range;
keys.add(sample);
}
if (keys.isEmpty())
{
// use an even tree distribution
tree.init();
}
else
{
int numkeys = keys.size();
Random random = new Random();
// sample the column family using random keys from the index
while (true)
{
DecoratedKey dk = keys.get(random.nextInt(numkeys));
if (!tree.split(dk.token))
break;
}
}
}
logger.debug("Prepared AEService tree of size " + tree.size() + " for " + request);
ranges = tree.invalids();
}
/**
* Called (in order) for every row present in the CF.
* Hashes the row, and adds it to the tree being built.
*
* There are four possible cases:
* 1. Token is greater than range.right (we haven't generated a range for it yet),
* 2. Token is less than/equal to range.left (the range was valid),
* 3. Token is contained in the range (the range is in progress),
* 4. No more invalid ranges exist.
*
* TODO: Because we only validate completely empty trees at the moment, we
* do not bother dealing with case 2 and case 4 should result in an error.
*
* Additionally, there is a special case for the minimum token, because
* although it sorts first, it is contained in the last possible range.
*
* @param row The row.
*/
public void add(AbstractCompactedRow row)
{
assert request.range.contains(row.key.token) : row.key.token + " is not contained in " + request.range;
assert lastKey == null || lastKey.compareTo(row.key) < 0
: "row " + row.key + " received out of order wrt " + lastKey;
lastKey = row.key;
if (range == null)
range = ranges.next();
// generate new ranges as long as case 1 is true
while (!range.contains(row.key.token))
{
// add the empty hash, and move to the next range
range.addHash(EMPTY_ROW);
range = ranges.next();
}
// case 3 must be true: mix in the hashed row
range.addHash(rowHash(row));
}
private MerkleTree.RowHash rowHash(AbstractCompactedRow row)
{
validated++;
// MerkleTree uses XOR internally, so we want lots of output bits here
MessageDigest digest = FBUtilities.newMessageDigest("SHA-256");
row.update(digest);
return new MerkleTree.RowHash(row.key.token, digest.digest());
}
/**
* Registers the newly created tree for rendezvous in Stage.ANTIENTROPY.
*/
public void complete()
{
completeTree();
StageManager.getStage(Stage.ANTI_ENTROPY).execute(this);
logger.debug("Validated " + validated + " rows into AEService tree for " + request);
}
void completeTree()
{
assert ranges != null : "Validator was not prepared()";
if (range != null)
range.addHash(EMPTY_ROW);
while (ranges.hasNext())
{
range = ranges.next();
range.addHash(EMPTY_ROW);
}
}
/**
* Called after the validation lifecycle to respond with the now valid tree. Runs in Stage.ANTIENTROPY.
*/
public void run()
{
// respond to the request that triggered this validation
AntiEntropyService.instance.respond(this, FBUtilities.getBroadcastAddress());
}
public MessageOut<Validator> createMessage()
{
return new MessageOut<Validator>(MessagingService.Verb.TREE_RESPONSE, this, Validator.serializer);
}
public static class ValidatorSerializer implements IVersionedSerializer<Validator>
{
public void serialize(Validator validator, DataOutput dos, int version) throws IOException
{
TreeRequest.serializer.serialize(validator.request, dos, version);
MerkleTree.serializer.serialize(validator.tree, dos, version);
}
public Validator deserialize(DataInput dis, int version) throws IOException
{
final TreeRequest request = TreeRequest.serializer.deserialize(dis, version);
try
{
return new Validator(request, MerkleTree.serializer.deserialize(dis, version));
}
catch(Exception e)
{
throw new RuntimeException(e);
}
}
public long serializedSize(Validator validator, int version)
{
return TreeRequest.serializer.serializedSize(validator.request, version)
+ MerkleTree.serializer.serializedSize(validator.tree, version);
}
}
}
/**
* Handler for requests from remote nodes to generate a valid tree.
* The payload is a CFPair representing the columnfamily to validate.
*/
public static class TreeRequestVerbHandler implements IVerbHandler<TreeRequest>
{
/**
* Trigger a validation compaction which will return the tree upon completion.
*/
public void doVerb(MessageIn<TreeRequest> message, String id)
{
TreeRequest remotereq = message.payload;
TreeRequest request = new TreeRequest(remotereq.sessionid, message.from, remotereq.range, remotereq.cf);
// trigger read-only compaction
ColumnFamilyStore store = Table.open(request.cf.left).getColumnFamilyStore(request.cf.right);
Validator validator = new Validator(request);
logger.debug("Queueing validation compaction for " + request);
CompactionManager.instance.submitValidation(store, validator);
}
}
/**
* Handler for responses from remote nodes which contain a valid tree.
* The payload is a completed Validator object from the remote endpoint.
*/
public static class TreeResponseVerbHandler implements IVerbHandler<Validator>
{
public void doVerb(MessageIn<Validator> message, String id)
{
// deserialize the remote tree, and register it
Validator response = message.payload;
TreeRequest request = new TreeRequest(response.request.sessionid, message.from, response.request.range, response.request.cf);
AntiEntropyService.instance.rendezvous(request, response.tree);
}
}
/**
* A tuple of table and cf.
*/
public static class CFPair extends Pair<String,String>
{
public CFPair(String table, String cf)
{
super(table, cf);
assert table != null && cf != null;
}
}
/**
* A tuple of table, cf, address and range that represents a location we have an outstanding TreeRequest for.
*/
public static class TreeRequest
{
public static final TreeRequestSerializer serializer = new TreeRequestSerializer();
public final String sessionid;
public final InetAddress endpoint;
public final Range<Token> range;
public final CFPair cf;
public TreeRequest(String sessionid, InetAddress endpoint, Range<Token> range, CFPair cf)
{
this.sessionid = sessionid;
this.endpoint = endpoint;
this.cf = cf;
this.range = range;
}
@Override
public final int hashCode()
{
return Objects.hashCode(sessionid, endpoint, cf, range);
}
@Override
public final boolean equals(Object o)
{
if(!(o instanceof TreeRequest))
return false;
TreeRequest that = (TreeRequest)o;
// handles nulls properly
return Objects.equal(sessionid, that.sessionid) && Objects.equal(endpoint, that.endpoint) && Objects.equal(cf, that.cf) && Objects.equal(range, that.range);
}
@Override
public String toString()
{
return "#<TreeRequest " + sessionid + ", " + endpoint + ", " + cf + ", " + range + ">";
}
public MessageOut<TreeRequest> createMessage()
{
return new MessageOut<TreeRequest>(MessagingService.Verb.TREE_REQUEST, this, TreeRequest.serializer);
}
public static class TreeRequestSerializer implements IVersionedSerializer<TreeRequest>
{
public void serialize(TreeRequest request, DataOutput dos, int version) throws IOException
{
dos.writeUTF(request.sessionid);
CompactEndpointSerializationHelper.serialize(request.endpoint, dos);
dos.writeUTF(request.cf.left);
dos.writeUTF(request.cf.right);
AbstractBounds.serializer.serialize(request.range, dos, version);
}
public TreeRequest deserialize(DataInput dis, int version) throws IOException
{
String sessId = dis.readUTF();
InetAddress endpoint = CompactEndpointSerializationHelper.deserialize(dis);
CFPair cfpair = new CFPair(dis.readUTF(), dis.readUTF());
Range<Token> range;
range = (Range<Token>) AbstractBounds.serializer.deserialize(dis, version);
return new TreeRequest(sessId, endpoint, range, cfpair);
}
public long serializedSize(TreeRequest request, int version)
{
return TypeSizes.NATIVE.sizeof(request.sessionid)
+ CompactEndpointSerializationHelper.serializedSize(request.endpoint)
+ TypeSizes.NATIVE.sizeof(request.cf.left)
+ TypeSizes.NATIVE.sizeof(request.cf.right)
+ AbstractBounds.serializer.serializedSize(request.range, version);
}
}
}
/**
* Triggers repairs with all neighbors for the given table, cfs and range.
* Typical lifecycle is: start() then join(). Executed in client threads.
*/
static class RepairSession extends WrappedRunnable implements IEndpointStateChangeSubscriber, IFailureDetectionEventListener
{
private final String sessionName;
private final boolean isSequential;
private final String tablename;
private final String[] cfnames;
private final Range<Token> range;
private volatile Exception exception;
private final AtomicBoolean isFailed = new AtomicBoolean(false);
private final Set<InetAddress> endpoints;
final Queue<RepairJob> jobs = new ConcurrentLinkedQueue<RepairJob>();
final Map<String, RepairJob> activeJobs = new ConcurrentHashMap<String, RepairJob>();
private final SimpleCondition completed = new SimpleCondition();
public final Condition differencingDone = new SimpleCondition();
private volatile boolean terminated = false;
public RepairSession(TreeRequest req, String tablename, String... cfnames)
{
this(req.sessionid, req.range, tablename, false, false, cfnames);
AntiEntropyService.instance.sessions.put(getName(), this);
}
public RepairSession(Range<Token> range, String tablename, boolean isSequential, boolean isLocal, String... cfnames)
{
this(UUIDGen.getTimeUUID().toString(), range, tablename, isSequential, isLocal, cfnames);
}
private RepairSession(String id, Range<Token> range, String tablename, boolean isSequential, boolean isLocal, String[] cfnames)
{
this.sessionName = id;
this.isSequential = isSequential;
this.tablename = tablename;
this.cfnames = cfnames;
assert cfnames.length > 0 : "Repairing no column families seems pointless, doesn't it";
this.range = range;
this.endpoints = AntiEntropyService.getNeighbors(tablename, range, isLocal);
}
public String getName()
{
return sessionName;
}
public Range<Token> getRange()
{
return range;
}
RepairFuture getFuture()
{
return new RepairFuture(this);
}
private String repairedNodes()
{
StringBuilder sb = new StringBuilder();
sb.append(FBUtilities.getBroadcastAddress());
for (InetAddress ep : endpoints)
sb.append(", ").append(ep);
return sb.toString();
}
// we don't care about the return value but care about it throwing exception
public void runMayThrow() throws Exception
{
logger.info(String.format("[repair #%s] new session: will sync %s on range %s for %s.%s", getName(), repairedNodes(), range, tablename, Arrays.toString(cfnames)));
if (endpoints.isEmpty())
{
differencingDone.signalAll();
logger.info(String.format("[repair #%s] No neighbors to repair with on range %s: session completed", getName(), range));
return;
}
// Checking all nodes are live
for (InetAddress endpoint : endpoints)
{
if (!FailureDetector.instance.isAlive(endpoint))
{
String message = String.format("Cannot proceed on repair because a neighbor (%s) is dead: session failed", endpoint);
differencingDone.signalAll();
logger.error(String.format("[repair #%s] ", getName()) + message);
throw new IOException(message);
}
if (MessagingService.instance().getVersion(endpoint) < MessagingService.VERSION_11 && isSequential)
{
logger.info(String.format("[repair #%s] Cannot repair using snapshots as node %s is pre-1.1", getName(), endpoint));
return;
}
}
AntiEntropyService.instance.sessions.put(getName(), this);
Gossiper.instance.register(this);
FailureDetector.instance.registerFailureDetectionEventListener(this);
try
{
// Create and queue a RepairJob for each column family
for (String cfname : cfnames)
{
RepairJob job = new RepairJob(cfname);
jobs.offer(job);
activeJobs.put(cfname, job);
}
jobs.peek().sendTreeRequests();
// block whatever thread started this session until all requests have been returned:
// if this thread dies, the session will still complete in the background
completed.await();
if (exception == null)
{
logger.info(String.format("[repair #%s] session completed successfully", getName()));
}
else
{
logger.error(String.format("[repair #%s] session completed with the following error", getName()), exception);
throw exception;
}
}
catch (InterruptedException e)
{
throw new RuntimeException("Interrupted while waiting for repair.");
}
finally
{
// mark this session as terminated
terminate();
FailureDetector.instance.unregisterFailureDetectionEventListener(this);
Gossiper.instance.unregister(this);
AntiEntropyService.instance.sessions.remove(getName());
}
}
/**
* @return wheather this session is terminated
*/
public boolean terminated()
{
return terminated;
}
public void terminate()
{
terminated = true;
for (RepairJob job : jobs)
job.terminate();
jobs.clear();
activeJobs.clear();
}
/**
* clear all RepairJobs and terminate this session.
*/
public void forceShutdown()
{
differencingDone.signalAll();
completed.signalAll();
}
void completed(Differencer differencer)
{
logger.debug(String.format("[repair #%s] Repair completed between %s and %s on %s",
getName(),
differencer.r1.endpoint,
differencer.r2.endpoint,
differencer.cfname));
RepairJob job = activeJobs.get(differencer.cfname);
if (job == null)
{
assert terminated;
return;
}
if (job.completedSynchronization(differencer))
{
activeJobs.remove(differencer.cfname);
String remaining = activeJobs.size() == 0 ? "" : String.format(" (%d remaining column family to sync for this session)", activeJobs.size());
logger.info(String.format("[repair #%s] %s is fully synced%s", getName(), differencer.cfname, remaining));
if (activeJobs.isEmpty())
completed.signalAll();
}
}
void failedNode(InetAddress remote)
{
String errorMsg = String.format("Endpoint %s died", remote);
exception = new IOException(errorMsg);
// If a node failed, we stop everything (though there could still be some activity in the background)
forceShutdown();
}
public void onJoin(InetAddress endpoint, EndpointState epState) {}
public void onChange(InetAddress endpoint, ApplicationState state, VersionedValue value) {}
public void onAlive(InetAddress endpoint, EndpointState state) {}
public void onDead(InetAddress endpoint, EndpointState state) {}
public void onRemove(InetAddress endpoint)
{
convict(endpoint, Double.MAX_VALUE);
}
public void onRestart(InetAddress endpoint, EndpointState epState)
{
convict(endpoint, Double.MAX_VALUE);
}
public void convict(InetAddress endpoint, double phi)
{
if (!endpoints.contains(endpoint))
return;
// We want a higher confidence in the failure detection than usual because failing a repair wrongly has a high cost.
if (phi < 2 * DatabaseDescriptor.getPhiConvictThreshold())
return;
// Though unlikely, it is possible to arrive here multiple time and we
// want to avoid print an error message twice
if (!isFailed.compareAndSet(false, true))
return;
failedNode(endpoint);
}
class RepairJob
{
private final String cfname;
// first we send tree requests. this tracks the endpoints remaining to hear from
private final RequestCoordinator<TreeRequest> treeRequests;
// tree responses are then tracked here
private final List<TreeResponse> trees = new ArrayList<TreeResponse>(endpoints.size() + 1);
// once all responses are received, each tree is compared with each other, and differencer tasks
// are submitted. the job is done when all differencers are complete.
private final RequestCoordinator<Differencer> differencers;
private final Condition requestsSent = new SimpleCondition();
private CountDownLatch snapshotLatch = null;
public RepairJob(String cfname)
{
this.cfname = cfname;
this.treeRequests = new RequestCoordinator<TreeRequest>(isSequential)
{
public void send(TreeRequest r)
{
MessagingService.instance().sendOneWay(r.createMessage(), r.endpoint);
}
};
this.differencers = new RequestCoordinator<Differencer>(isSequential)
{
public void send(Differencer d)
{
StageManager.getStage(Stage.ANTI_ENTROPY).execute(d);
}
};
}
/**
* Send merkle tree request to every involved neighbor.
*/
public void sendTreeRequests()
{
// send requests to all nodes
List<InetAddress> allEndpoints = new ArrayList<InetAddress>(endpoints);
allEndpoints.add(FBUtilities.getBroadcastAddress());
if (isSequential)
makeSnapshots(endpoints);
for (InetAddress endpoint : allEndpoints)
treeRequests.add(new TreeRequest(getName(), endpoint, range, new CFPair(tablename, cfname)));
logger.info(String.format("[repair #%s] requesting merkle trees for %s (to %s)", getName(), cfname, allEndpoints));
treeRequests.start();
requestsSent.signalAll();
}
public void makeSnapshots(Collection<InetAddress> endpoints)
{
try
{
snapshotLatch = new CountDownLatch(endpoints.size());
IAsyncCallback callback = new IAsyncCallback()
{
public boolean isLatencyForSnitch()
{
return false;
}
public void response(MessageIn msg)
{
RepairJob.this.snapshotLatch.countDown();
}
};
for (InetAddress endpoint : endpoints)
MessagingService.instance().sendRR(new SnapshotCommand(tablename, cfname, sessionName, false).createMessage(), endpoint, callback);
snapshotLatch.await();
snapshotLatch = null;
}
catch (InterruptedException e)
{
throw new RuntimeException(e);
}
}
/**
* Add a new received tree and return the number of remaining tree to
* be received for the job to be complete.
*
* Callers may assume exactly one addTree call will result in zero remaining endpoints.
*/
public synchronized int addTree(TreeRequest request, MerkleTree tree)
{
// Wait for all request to have been performed (see #3400)
try
{
requestsSent.await();
}
catch (InterruptedException e)
{
throw new AssertionError("Interrupted while waiting for requests to be sent");
}
assert request.cf.right.equals(cfname);
trees.add(new TreeResponse(request.endpoint, tree));
return treeRequests.completed(request);
}
/**
* Submit differencers for running.
* All tree *must* have been received before this is called.
*/
public void submitDifferencers()
{
// We need to difference all trees one against another
for (int i = 0; i < trees.size() - 1; ++i)
{
TreeResponse r1 = trees.get(i);
for (int j = i + 1; j < trees.size(); ++j)
{
TreeResponse r2 = trees.get(j);
Differencer differencer = new Differencer(cfname, r1, r2);
logger.debug("Queueing comparison {}", differencer);
differencers.add(differencer);
}
}
differencers.start();
trees.clear(); // allows gc to do its thing
}
/**
* @return true if the @param differencer was the last remaining
*/
synchronized boolean completedSynchronization(Differencer differencer)
{
return differencers.completed(differencer) == 0;
}
public void terminate()
{
if (snapshotLatch != null)
{
while (snapshotLatch.getCount() > 0)
snapshotLatch.countDown();
}
}
}
/**
* Runs on the node that initiated a request to compare two trees, and launch repairs for disagreeing ranges.
*/
class Differencer implements Runnable
{
public final String cfname;
public final TreeResponse r1;
public final TreeResponse r2;
public final List<Range<Token>> differences = new ArrayList<Range<Token>>();
Differencer(String cfname, TreeResponse r1, TreeResponse r2)
{
this.cfname = cfname;
this.r1 = r1;
this.r2 = r2;
}
/**
* Compares our trees, and triggers repairs for any ranges that mismatch.
*/
public void run()
{
// restore partitioners (in case we were serialized)
if (r1.tree.partitioner() == null)
r1.tree.partitioner(StorageService.getPartitioner());
if (r2.tree.partitioner() == null)
r2.tree.partitioner(StorageService.getPartitioner());
// compare trees, and collect differences
differences.addAll(MerkleTree.difference(r1.tree, r2.tree));
// choose a repair method based on the significance of the difference
String format = String.format("[repair #%s] Endpoints %s and %s %%s for %s", getName(), r1.endpoint, r2.endpoint, cfname);
if (differences.isEmpty())
{
logger.info(String.format(format, "are consistent"));
completed(this);
return;
}
// non-0 difference: perform streaming repair
logger.info(String.format(format, "have " + differences.size() + " range(s) out of sync"));
performStreamingRepair();
}
/**
* Starts sending/receiving our list of differences to/from the remote endpoint: creates a callback
* that will be called out of band once the streams complete.
*/
void performStreamingRepair()
{
Runnable callback = new Runnable()
{
public void run()
{
completed(Differencer.this);
}
};
StreamingRepairTask task = StreamingRepairTask.create(r1.endpoint, r2.endpoint, tablename, cfname, differences, callback);
// Pre 1.0, nodes don't know how to handle forwarded streaming task so don't bother
if (task.isLocalTask() || MessagingService.instance().getVersion(task.dst) >= MessagingService.VERSION_10)
task.run();
}
public String toString()
{
return "#<Differencer " + r1.endpoint + "<->" + r2.endpoint + "/" + range + ">";
}
}
}
static class TreeResponse
{
public final InetAddress endpoint;
public final MerkleTree tree;
TreeResponse(InetAddress endpoint, MerkleTree tree)
{
this.endpoint = endpoint;
this.tree = tree;
}
}
public static class RepairFuture extends FutureTask
{
public final RepairSession session;
RepairFuture(RepairSession session)
{
super(session, null);
this.session = session;
}
}
public static abstract class RequestCoordinator<R>
{
private final Order<R> orderer;
protected RequestCoordinator(boolean isSequential)
{
this.orderer = isSequential ? new SequentialOrder(this) : new ParallelOrder(this);
}
public abstract void send(R request);
public void add(R request)
{
orderer.add(request);
}
public void start()
{
orderer.start();
}
// Returns how many request remains
public int completed(R request)
{
return orderer.completed(request);
}
private static abstract class Order<R>
{
protected final RequestCoordinator<R> coordinator;
Order(RequestCoordinator<R> coordinator)
{
this.coordinator = coordinator;
}
public abstract void add(R request);
public abstract void start();
public abstract int completed(R request);
}
private static class SequentialOrder<R> extends Order<R>
{
private final Queue<R> requests = new LinkedList<R>();
SequentialOrder(RequestCoordinator<R> coordinator)
{
super(coordinator);
}
public void add(R request)
{
requests.add(request);
}
public void start()
{
if (requests.isEmpty())
return;
coordinator.send(requests.peek());
}
public int completed(R request)
{
assert request.equals(requests.peek());
requests.poll();
int remaining = requests.size();
if (remaining != 0)
coordinator.send(requests.peek());
return remaining;
}
}
private static class ParallelOrder<R> extends Order<R>
{
private final Set<R> requests = new HashSet<R>();
ParallelOrder(RequestCoordinator<R> coordinator)
{
super(coordinator);
}
public void add(R request)
{
requests.add(request);
}
public void start()
{
for (R request : requests)
coordinator.send(request);
}
public int completed(R request)
{
requests.remove(request);
return requests.size();
}
}
}
}