/*
* 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.db;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicLong;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Iterables;
import com.google.common.util.concurrent.RateLimiter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.concurrent.DebuggableScheduledThreadPoolExecutor;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.cql3.QueryProcessor;
import org.apache.cassandra.cql3.UntypedResultSet;
import org.apache.cassandra.db.compaction.CompactionManager;
import org.apache.cassandra.db.marshal.LongType;
import org.apache.cassandra.db.marshal.UTF8Type;
import org.apache.cassandra.db.marshal.UUIDType;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.exceptions.WriteTimeoutException;
import org.apache.cassandra.gms.FailureDetector;
import org.apache.cassandra.io.sstable.Descriptor;
import org.apache.cassandra.io.sstable.SSTableReader;
import org.apache.cassandra.io.util.FastByteArrayOutputStream;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.service.StorageProxy;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.service.WriteResponseHandler;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.WrappedRunnable;
public class BatchlogManager implements BatchlogManagerMBean
{
private static final String MBEAN_NAME = "org.apache.cassandra.db:type=BatchlogManager";
private static final long REPLAY_INTERVAL = 60 * 1000; // milliseconds
private static final int PAGE_SIZE = 128; // same as HHOM, for now, w/out using any heuristics. TODO: set based on avg batch size.
private static final Logger logger = LoggerFactory.getLogger(BatchlogManager.class);
public static final BatchlogManager instance = new BatchlogManager();
private final AtomicLong totalBatchesReplayed = new AtomicLong();
// Single-thread executor service for scheduling and serializing log replay.
public static final ScheduledExecutorService batchlogTasks = new DebuggableScheduledThreadPoolExecutor("BatchlogTasks");
public void start()
{
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
try
{
mbs.registerMBean(this, new ObjectName(MBEAN_NAME));
}
catch (Exception e)
{
throw new RuntimeException(e);
}
Runnable runnable = new WrappedRunnable()
{
public void runMayThrow() throws ExecutionException, InterruptedException
{
replayAllFailedBatches();
}
};
batchlogTasks.scheduleWithFixedDelay(runnable, StorageService.RING_DELAY, REPLAY_INTERVAL, TimeUnit.MILLISECONDS);
}
public int countAllBatches()
{
return (int) process("SELECT count(*) FROM %s.%s", Keyspace.SYSTEM_KS, SystemKeyspace.BATCHLOG_CF).one().getLong("count");
}
public long getTotalBatchesReplayed()
{
return totalBatchesReplayed.longValue();
}
public void forceBatchlogReplay()
{
startBatchlogReplay();
}
public Future<?> startBatchlogReplay()
{
Runnable runnable = new WrappedRunnable()
{
public void runMayThrow() throws ExecutionException, InterruptedException
{
replayAllFailedBatches();
}
};
// If a replay is already in progress this request will be executed after it completes.
return batchlogTasks.submit(runnable);
}
public static RowMutation getBatchlogMutationFor(Collection<RowMutation> mutations, UUID uuid)
{
return getBatchlogMutationFor(mutations, uuid, FBUtilities.timestampMicros());
}
@VisibleForTesting
static RowMutation getBatchlogMutationFor(Collection<RowMutation> mutations, UUID uuid, long now)
{
ByteBuffer writtenAt = LongType.instance.decompose(now / 1000);
ByteBuffer data = serializeRowMutations(mutations);
ColumnFamily cf = ArrayBackedSortedColumns.factory.create(CFMetaData.BatchlogCf);
cf.addColumn(new Column(columnName(""), ByteBufferUtil.EMPTY_BYTE_BUFFER, now));
cf.addColumn(new Column(columnName("data"), data, now));
cf.addColumn(new Column(columnName("written_at"), writtenAt, now));
return new RowMutation(Keyspace.SYSTEM_KS, UUIDType.instance.decompose(uuid), cf);
}
private static ByteBuffer serializeRowMutations(Collection<RowMutation> mutations)
{
FastByteArrayOutputStream bos = new FastByteArrayOutputStream();
DataOutputStream out = new DataOutputStream(bos);
try
{
out.writeInt(mutations.size());
for (RowMutation rm : mutations)
RowMutation.serializer.serialize(rm, out, MessagingService.VERSION_12);
}
catch (IOException e)
{
throw new AssertionError(); // cannot happen.
}
return ByteBuffer.wrap(bos.toByteArray());
}
private void replayAllFailedBatches() throws ExecutionException, InterruptedException
{
logger.debug("Started replayAllFailedBatches");
// rate limit is in bytes per second. Uses Double.MAX_VALUE if disabled (set to 0 in cassandra.yaml).
// max rate is scaled by the number of nodes in the cluster (same as for HHOM - see CASSANDRA-5272).
int throttleInKB = DatabaseDescriptor.getBatchlogReplayThrottleInKB() / StorageService.instance.getTokenMetadata().getAllEndpoints().size();
RateLimiter rateLimiter = RateLimiter.create(throttleInKB == 0 ? Double.MAX_VALUE : throttleInKB * 1024);
UntypedResultSet page = process("SELECT id, data, written_at, version FROM %s.%s LIMIT %d",
Keyspace.SYSTEM_KS,
SystemKeyspace.BATCHLOG_CF,
PAGE_SIZE);
while (!page.isEmpty())
{
UUID id = processBatchlogPage(page, rateLimiter);
if (page.size() < PAGE_SIZE)
break; // we've exhausted the batchlog, next query would be empty.
page = process("SELECT id, data, written_at, version FROM %s.%s WHERE token(id) > token(%s) LIMIT %d",
Keyspace.SYSTEM_KS,
SystemKeyspace.BATCHLOG_CF,
id,
PAGE_SIZE);
}
cleanup();
logger.debug("Finished replayAllFailedBatches");
}
// returns the UUID of the last seen batch
private UUID processBatchlogPage(UntypedResultSet page, RateLimiter rateLimiter)
{
UUID id = null;
for (UntypedResultSet.Row row : page)
{
id = row.getUUID("id");
long writtenAt = row.getLong("written_at");
int version = row.has("version") ? row.getInt("version") : MessagingService.VERSION_12;
// enough time for the actual write + batchlog entry mutation delivery (two separate requests).
long timeout = getBatchlogTimeout();
if (System.currentTimeMillis() < writtenAt + timeout)
continue; // not ready to replay yet, might still get a deletion.
replayBatch(id, row.getBytes("data"), writtenAt, version, rateLimiter);
}
return id;
}
public long getBatchlogTimeout()
{
return DatabaseDescriptor.getWriteRpcTimeout() * 2; // enough time for the actual write + BM removal mutation
}
private void replayBatch(UUID id, ByteBuffer data, long writtenAt, int version, RateLimiter rateLimiter)
{
logger.debug("Replaying batch {}", id);
try
{
replaySerializedMutations(data, writtenAt, version, rateLimiter);
}
catch (IOException e)
{
logger.warn("Skipped batch replay of {} due to {}", id, e);
}
deleteBatch(id);
totalBatchesReplayed.incrementAndGet();
}
private void deleteBatch(UUID id)
{
RowMutation mutation = new RowMutation(Keyspace.SYSTEM_KS, UUIDType.instance.decompose(id));
mutation.delete(SystemKeyspace.BATCHLOG_CF, FBUtilities.timestampMicros());
mutation.apply();
}
private void replaySerializedMutations(ByteBuffer data, long writtenAt, int version, RateLimiter rateLimiter) throws IOException
{
DataInputStream in = new DataInputStream(ByteBufferUtil.inputStream(data));
int size = in.readInt();
List<RowMutation> mutations = new ArrayList<>(size);
for (int i = 0; i < size; i++)
{
RowMutation mutation = RowMutation.serializer.deserialize(in, version);
// Remove CFs that have been truncated since. writtenAt and SystemTable#getTruncatedAt() both return millis.
// We don't abort the replay entirely b/c this can be considered a succes (truncated is same as delivered then
// truncated.
for (UUID cfId : mutation.getColumnFamilyIds())
if (writtenAt <= SystemKeyspace.getTruncatedAt(cfId))
mutation = mutation.without(cfId);
if (!mutation.isEmpty())
mutations.add(mutation);
}
if (!mutations.isEmpty())
replayMutations(mutations, writtenAt, version, rateLimiter);
}
/*
* We try to deliver the mutations to the replicas ourselves if they are alive and only resort to writing hints
* when a replica is down or a write request times out.
*/
private void replayMutations(List<RowMutation> mutations, long writtenAt, int version, RateLimiter rateLimiter) throws IOException
{
int ttl = calculateHintTTL(mutations, writtenAt);
if (ttl <= 0)
return; // this batchlog entry has 'expired'
List<InetAddress> liveEndpoints = new ArrayList<>();
List<InetAddress> hintEndpoints = new ArrayList<>();
for (RowMutation mutation : mutations)
{
String ks = mutation.getKeyspaceName();
Token tk = StorageService.getPartitioner().getToken(mutation.key());
int mutationSize = (int) RowMutation.serializer.serializedSize(mutation, version);
for (InetAddress endpoint : Iterables.concat(StorageService.instance.getNaturalEndpoints(ks, tk),
StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, ks)))
{
rateLimiter.acquire(mutationSize);
if (endpoint.equals(FBUtilities.getBroadcastAddress()))
mutation.apply();
else if (FailureDetector.instance.isAlive(endpoint))
liveEndpoints.add(endpoint); // will try delivering directly instead of writing a hint.
else
hintEndpoints.add(endpoint);
}
if (!liveEndpoints.isEmpty())
hintEndpoints.addAll(attemptDirectDelivery(mutation, liveEndpoints));
for (InetAddress endpoint : hintEndpoints)
StorageProxy.writeHintForMutation(mutation, writtenAt, ttl, endpoint);
liveEndpoints.clear();
hintEndpoints.clear();
}
}
// Returns the endpoints we failed to deliver to.
private Set<InetAddress> attemptDirectDelivery(RowMutation mutation, List<InetAddress> endpoints) throws IOException
{
final List<WriteResponseHandler> handlers = new ArrayList<>();
final Set<InetAddress> undelivered = Collections.synchronizedSet(new HashSet<InetAddress>());
for (final InetAddress ep : endpoints)
{
Runnable callback = new Runnable()
{
public void run()
{
undelivered.remove(ep);
}
};
WriteResponseHandler handler = new WriteResponseHandler(ep, WriteType.UNLOGGED_BATCH, callback);
MessagingService.instance().sendRR(mutation.createMessage(), ep, handler, false);
handlers.add(handler);
}
// Wait for all the requests to complete.
for (WriteResponseHandler handler : handlers)
{
try
{
handler.get();
}
catch (WriteTimeoutException e)
{
logger.debug("Timed out replaying a batched mutation to a node, will write a hint");
}
}
return undelivered;
}
/*
* Calculate ttl for the mutations' hints (and reduce ttl by the time the mutations spent in the batchlog).
* This ensures that deletes aren't "undone" by an old batch replay.
*/
private int calculateHintTTL(List<RowMutation> mutations, long writtenAt)
{
int unadjustedTTL = Integer.MAX_VALUE;
for (RowMutation mutation : mutations)
unadjustedTTL = Math.min(unadjustedTTL, HintedHandOffManager.calculateHintTTL(mutation));
return unadjustedTTL - (int) TimeUnit.MILLISECONDS.toSeconds(System.currentTimeMillis() - writtenAt);
}
private static ByteBuffer columnName(String name)
{
return CFMetaData.BatchlogCf.getCfDef().getColumnNameBuilder().add(UTF8Type.instance.decompose(name)).build();
}
// force flush + compaction to reclaim space from the replayed batches
private void cleanup() throws ExecutionException, InterruptedException
{
ColumnFamilyStore cfs = Keyspace.open(Keyspace.SYSTEM_KS).getColumnFamilyStore(SystemKeyspace.BATCHLOG_CF);
cfs.forceBlockingFlush();
Collection<Descriptor> descriptors = new ArrayList<>();
for (SSTableReader sstr : cfs.getSSTables())
descriptors.add(sstr.descriptor);
if (!descriptors.isEmpty()) // don't pollute the logs if there is nothing to compact.
CompactionManager.instance.submitUserDefined(cfs, descriptors, Integer.MAX_VALUE).get();
}
private static UntypedResultSet process(String format, Object... args)
{
return QueryProcessor.processInternal(String.format(format, args));
}
}