/*
* 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.commitlog;
import java.io.*;
import java.lang.management.ManagementFactory;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.zip.CRC32;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import com.google.common.annotations.VisibleForTesting;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.commons.lang3.StringUtils;
import org.apache.cassandra.config.Config;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.config.ParameterizedClass;
import org.apache.cassandra.db.*;
import org.apache.cassandra.io.FSWriteError;
import org.apache.cassandra.schema.CompressionParams;
import org.apache.cassandra.io.compress.ICompressor;
import org.apache.cassandra.io.util.BufferedDataOutputStreamPlus;
import org.apache.cassandra.io.util.DataOutputBufferFixed;
import org.apache.cassandra.metrics.CommitLogMetrics;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.utils.JVMStabilityInspector;
import static org.apache.cassandra.db.commitlog.CommitLogSegment.*;
import static org.apache.cassandra.utils.FBUtilities.updateChecksum;
import static org.apache.cassandra.utils.FBUtilities.updateChecksumInt;
/*
* Commit Log tracks every write operation into the system. The aim of the commit log is to be able to
* successfully recover data that was not stored to disk via the Memtable.
*/
public class CommitLog implements CommitLogMBean
{
private static final Logger logger = LoggerFactory.getLogger(CommitLog.class);
public static final CommitLog instance = CommitLog.construct();
// we only permit records HALF the size of a commit log, to ensure we don't spin allocating many mostly
// empty segments when writing large records
private final long MAX_MUTATION_SIZE = DatabaseDescriptor.getMaxMutationSize();
public final CommitLogSegmentManager allocator;
public final CommitLogArchiver archiver;
final CommitLogMetrics metrics;
final AbstractCommitLogService executor;
volatile Configuration configuration;
final public String location;
private static CommitLog construct()
{
CommitLog log = new CommitLog(DatabaseDescriptor.getCommitLogLocation(), CommitLogArchiver.construct());
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
try
{
mbs.registerMBean(log, new ObjectName("org.apache.cassandra.db:type=Commitlog"));
}
catch (Exception e)
{
throw new RuntimeException(e);
}
return log.start();
}
@VisibleForTesting
CommitLog(String location, CommitLogArchiver archiver)
{
this.location = location;
this.configuration = new Configuration(DatabaseDescriptor.getCommitLogCompression());
DatabaseDescriptor.createAllDirectories();
this.archiver = archiver;
metrics = new CommitLogMetrics();
executor = DatabaseDescriptor.getCommitLogSync() == Config.CommitLogSync.batch
? new BatchCommitLogService(this)
: new PeriodicCommitLogService(this);
allocator = new CommitLogSegmentManager(this);
// register metrics
metrics.attach(executor, allocator);
}
CommitLog start()
{
executor.start();
allocator.start();
return this;
}
/**
* Perform recovery on commit logs located in the directory specified by the config file.
*
* @return the number of mutations replayed
*/
public int recover() throws IOException
{
// If createReserveSegments is already flipped, the CLSM is running and recovery has already taken place.
if (allocator.createReserveSegments)
return 0;
FilenameFilter unmanagedFilesFilter = new FilenameFilter()
{
public boolean accept(File dir, String name)
{
// we used to try to avoid instantiating commitlog (thus creating an empty segment ready for writes)
// until after recover was finished. this turns out to be fragile; it is less error-prone to go
// ahead and allow writes before recover(), and just skip active segments when we do.
return CommitLogDescriptor.isValid(name) && CommitLogSegment.shouldReplay(name);
}
};
// submit all existing files in the commit log dir for archiving prior to recovery - CASSANDRA-6904
for (File file : new File(DatabaseDescriptor.getCommitLogLocation()).listFiles(unmanagedFilesFilter))
{
archiver.maybeArchive(file.getPath(), file.getName());
archiver.maybeWaitForArchiving(file.getName());
}
assert archiver.archivePending.isEmpty() : "Not all commit log archive tasks were completed before restore";
archiver.maybeRestoreArchive();
File[] files = new File(DatabaseDescriptor.getCommitLogLocation()).listFiles(unmanagedFilesFilter);
int replayed = 0;
if (files.length == 0)
{
logger.info("No commitlog files found; skipping replay");
}
else
{
Arrays.sort(files, new CommitLogSegmentFileComparator());
logger.info("Replaying {}", StringUtils.join(files, ", "));
replayed = recover(files);
logger.info("Log replay complete, {} replayed mutations", replayed);
for (File f : files)
allocator.recycleSegment(f);
}
allocator.enableReserveSegmentCreation();
return replayed;
}
/**
* Perform recovery on a list of commit log files.
*
* @param clogs the list of commit log files to replay
* @return the number of mutations replayed
*/
public int recover(File... clogs) throws IOException
{
CommitLogReplayer recovery = CommitLogReplayer.construct(this);
recovery.recover(clogs);
return recovery.blockForWrites();
}
/**
* Perform recovery on a single commit log.
*/
public void recover(String path) throws IOException
{
CommitLogReplayer recovery = CommitLogReplayer.construct(this);
recovery.recover(new File(path), false);
recovery.blockForWrites();
}
/**
* @return a ReplayPosition which, if >= one returned from add(), implies add() was started
* (but not necessarily finished) prior to this call
*/
public ReplayPosition getContext()
{
return allocator.allocatingFrom().getContext();
}
/**
* Flushes all dirty CFs, waiting for them to free and recycle any segments they were retaining
*/
public void forceRecycleAllSegments(Iterable<UUID> droppedCfs)
{
allocator.forceRecycleAll(droppedCfs);
}
/**
* Flushes all dirty CFs, waiting for them to free and recycle any segments they were retaining
*/
public void forceRecycleAllSegments()
{
allocator.forceRecycleAll(Collections.<UUID>emptyList());
}
/**
* Forces a disk flush on the commit log files that need it. Blocking.
*/
public void sync(boolean syncAllSegments)
{
CommitLogSegment current = allocator.allocatingFrom();
for (CommitLogSegment segment : allocator.getActiveSegments())
{
if (!syncAllSegments && segment.id > current.id)
return;
segment.sync();
}
}
/**
* Preempts the CLExecutor, telling to to sync immediately
*/
public void requestExtraSync()
{
executor.requestExtraSync();
}
/**
* Add a Mutation to the commit log.
*
* @param mutation the Mutation to add to the log
*/
public ReplayPosition add(Mutation mutation)
{
assert mutation != null;
int size = (int) Mutation.serializer.serializedSize(mutation, MessagingService.current_version);
int totalSize = size + ENTRY_OVERHEAD_SIZE;
if (totalSize > MAX_MUTATION_SIZE)
{
throw new IllegalArgumentException(String.format("Mutation of %s bytes is too large for the maximum size of %s",
totalSize, MAX_MUTATION_SIZE));
}
Allocation alloc = allocator.allocate(mutation, (int) totalSize);
CRC32 checksum = new CRC32();
final ByteBuffer buffer = alloc.getBuffer();
try (BufferedDataOutputStreamPlus dos = new DataOutputBufferFixed(buffer))
{
// checksummed length
dos.writeInt(size);
updateChecksumInt(checksum, size);
buffer.putInt((int) checksum.getValue());
// checksummed mutation
Mutation.serializer.serialize(mutation, dos, MessagingService.current_version);
updateChecksum(checksum, buffer, buffer.position() - size, size);
buffer.putInt((int) checksum.getValue());
}
catch (IOException e)
{
throw new FSWriteError(e, alloc.getSegment().getPath());
}
finally
{
alloc.markWritten();
}
executor.finishWriteFor(alloc);
return alloc.getReplayPosition();
}
/**
* Modifies the per-CF dirty cursors of any commit log segments for the column family according to the position
* given. Discards any commit log segments that are no longer used.
*
* @param cfId the column family ID that was flushed
* @param lowerBound the lowest covered replay position of the flush
* @param lowerBound the highest covered replay position of the flush
*/
public void discardCompletedSegments(final UUID cfId, final ReplayPosition lowerBound, final ReplayPosition upperBound)
{
logger.trace("discard completed log segments for {}-{}, table {}", lowerBound, upperBound, cfId);
// Go thru the active segment files, which are ordered oldest to newest, marking the
// flushed CF as clean, until we reach the segment file containing the ReplayPosition passed
// in the arguments. Any segments that become unused after they are marked clean will be
// recycled or discarded.
for (Iterator<CommitLogSegment> iter = allocator.getActiveSegments().iterator(); iter.hasNext();)
{
CommitLogSegment segment = iter.next();
segment.markClean(cfId, lowerBound, upperBound);
if (segment.isUnused())
{
logger.trace("Commit log segment {} is unused", segment);
allocator.recycleSegment(segment);
}
else
{
logger.trace("Not safe to delete{} commit log segment {}; dirty is {}",
(iter.hasNext() ? "" : " active"), segment, segment.dirtyString());
}
// Don't mark or try to delete any newer segments once we've reached the one containing the
// position of the flush.
if (segment.contains(upperBound))
break;
}
}
@Override
public String getArchiveCommand()
{
return archiver.archiveCommand;
}
@Override
public String getRestoreCommand()
{
return archiver.restoreCommand;
}
@Override
public String getRestoreDirectories()
{
return archiver.restoreDirectories;
}
@Override
public long getRestorePointInTime()
{
return archiver.restorePointInTime;
}
@Override
public String getRestorePrecision()
{
return archiver.precision.toString();
}
public List<String> getActiveSegmentNames()
{
List<String> segmentNames = new ArrayList<>();
for (CommitLogSegment segment : allocator.getActiveSegments())
segmentNames.add(segment.getName());
return segmentNames;
}
public List<String> getArchivingSegmentNames()
{
return new ArrayList<>(archiver.archivePending.keySet());
}
@Override
public long getActiveContentSize()
{
long size = 0;
for (CommitLogSegment segment : allocator.getActiveSegments())
size += segment.contentSize();
return size;
}
@Override
public long getActiveOnDiskSize()
{
return allocator.onDiskSize();
}
@Override
public Map<String, Double> getActiveSegmentCompressionRatios()
{
Map<String, Double> segmentRatios = new TreeMap<>();
for (CommitLogSegment segment : allocator.getActiveSegments())
segmentRatios.put(segment.getName(), 1.0 * segment.onDiskSize() / segment.contentSize());
return segmentRatios;
}
/**
* Shuts down the threads used by the commit log, blocking until completion.
*/
public void shutdownBlocking() throws InterruptedException
{
executor.shutdown();
executor.awaitTermination();
allocator.shutdown();
allocator.awaitTermination();
}
/**
* FOR TESTING PURPOSES. See CommitLogAllocator.
* @return the number of files recovered
*/
public int resetUnsafe(boolean deleteSegments) throws IOException
{
stopUnsafe(deleteSegments);
resetConfiguration();
return restartUnsafe();
}
/**
* FOR TESTING PURPOSES. See CommitLogAllocator.
*/
public void stopUnsafe(boolean deleteSegments)
{
executor.shutdown();
try
{
executor.awaitTermination();
}
catch (InterruptedException e)
{
throw new RuntimeException(e);
}
allocator.stopUnsafe(deleteSegments);
CommitLogSegment.resetReplayLimit();
}
/**
* FOR TESTING PURPOSES.
*/
public void resetConfiguration()
{
configuration = new Configuration(DatabaseDescriptor.getCommitLogCompression());
}
/**
* FOR TESTING PURPOSES. See CommitLogAllocator
*/
public int restartUnsafe() throws IOException
{
allocator.start();
executor.restartUnsafe();
try
{
return recover();
}
catch (FSWriteError e)
{
// Workaround for a class of races that keeps showing up on Windows tests.
// stop/start/reset path on Windows with segment deletion is very touchy/brittle
// and the timing keeps getting screwed up. Rather than chasing our tail further
// or rewriting the CLSM, just report that we didn't recover anything back up
// the chain. This will silence most intermittent test failures on Windows
// and appropriately fail tests that expected segments to be recovered that
// were not.
return 0;
}
}
/**
* Used by tests.
*
* @return the number of active segments (segments with unflushed data in them)
*/
public int activeSegments()
{
return allocator.getActiveSegments().size();
}
@VisibleForTesting
public static boolean handleCommitError(String message, Throwable t)
{
JVMStabilityInspector.inspectCommitLogThrowable(t);
switch (DatabaseDescriptor.getCommitFailurePolicy())
{
// Needed here for unit tests to not fail on default assertion
case die:
case stop:
StorageService.instance.stopTransports();
//$FALL-THROUGH$
case stop_commit:
logger.error(String.format("%s. Commit disk failure policy is %s; terminating thread", message, DatabaseDescriptor.getCommitFailurePolicy()), t);
return false;
case ignore:
logger.error(message, t);
return true;
default:
throw new AssertionError(DatabaseDescriptor.getCommitFailurePolicy());
}
}
public static final class Configuration
{
/**
* The compressor class.
*/
private final ParameterizedClass compressorClass;
/**
* The compressor used to compress the segments.
*/
private final ICompressor compressor;
public Configuration(ParameterizedClass compressorClass)
{
this.compressorClass = compressorClass;
this.compressor = compressorClass != null ? CompressionParams.createCompressor(compressorClass) : null;
}
/**
* Checks if the segments must be compressed.
* @return <code>true</code> if the segments must be compressed, <code>false</code> otherwise.
*/
public boolean useCompression()
{
return compressor != null;
}
/**
* Returns the compressor used to compress the segments.
* @return the compressor used to compress the segments
*/
public ICompressor getCompressor()
{
return compressor;
}
/**
* Returns the compressor class.
* @return the compressor class
*/
public ParameterizedClass getCompressorClass()
{
return compressorClass;
}
/**
* Returns the compressor name.
* @return the compressor name.
*/
public String getCompressorName()
{
return useCompression() ? compressor.getClass().getSimpleName() : "none";
}
}
}