/**
* 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.kahadb.journal;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.RandomAccessFile;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicReference;
import java.util.zip.Adler32;
import java.util.zip.Checksum;
import org.apache.kahadb.util.ByteSequence;
import org.apache.kahadb.util.DataByteArrayOutputStream;
import org.apache.kahadb.util.LinkedNode;
import org.apache.kahadb.util.LinkedNodeList;
/**
* An optimized writer to do batch appends to a data file. This object is thread
* safe and gains throughput as you increase the number of concurrent writes it
* does.
*
* @version $Revision: 882511 $
*/
class DataFileAppender {
protected final Journal journal;
protected final Map<WriteKey, WriteCommand> inflightWrites;
protected final Object enqueueMutex = new Object() {
};
protected WriteBatch nextWriteBatch;
protected boolean shutdown;
protected IOException firstAsyncException;
protected final CountDownLatch shutdownDone = new CountDownLatch(1);
protected int maxWriteBatchSize;
private boolean running;
private Thread thread;
public static class WriteKey {
private final int file;
private final long offset;
private final int hash;
public WriteKey(Location item) {
file = item.getDataFileId();
offset = item.getOffset();
// TODO: see if we can build a better hash
hash = (int)(file ^ offset);
}
public int hashCode() {
return hash;
}
public boolean equals(Object obj) {
if (obj instanceof WriteKey) {
WriteKey di = (WriteKey)obj;
return di.file == file && di.offset == offset;
}
return false;
}
}
public class WriteBatch {
public final DataFile dataFile;
public final LinkedNodeList<WriteCommand> writes = new LinkedNodeList<WriteCommand>();
public final CountDownLatch latch = new CountDownLatch(1);
private final int offset;
public int size = Journal.BATCH_CONTROL_RECORD_SIZE;
public AtomicReference<IOException> exception = new AtomicReference<IOException>();
public WriteBatch(DataFile dataFile, int offset, WriteCommand write) throws IOException {
this.dataFile = dataFile;
this.offset = offset;
this.dataFile.incrementLength(Journal.BATCH_CONTROL_RECORD_SIZE);
this.size=Journal.BATCH_CONTROL_RECORD_SIZE;
journal.addToTotalLength(Journal.BATCH_CONTROL_RECORD_SIZE);
append(write);
}
public boolean canAppend(WriteCommand write) {
int newSize = size + write.location.getSize();
if (newSize >= maxWriteBatchSize || offset+newSize > journal.getMaxFileLength() ) {
return false;
}
return true;
}
public void append(WriteCommand write) throws IOException {
this.writes.addLast(write);
write.location.setDataFileId(dataFile.getDataFileId());
write.location.setOffset(offset+size);
int s = write.location.getSize();
size += s;
dataFile.incrementLength(s);
journal.addToTotalLength(s);
}
}
public static class WriteCommand extends LinkedNode<WriteCommand> {
public final Location location;
public final ByteSequence data;
final boolean sync;
public final Runnable onComplete;
public WriteCommand(Location location, ByteSequence data, boolean sync) {
this.location = location;
this.data = data;
this.sync = sync;
this.onComplete = null;
}
public WriteCommand(Location location, ByteSequence data, Runnable onComplete) {
this.location = location;
this.data = data;
this.onComplete = onComplete;
this.sync = false;
}
}
/**
* Construct a Store writer
*
* @param fileId
*/
public DataFileAppender(Journal dataManager) {
this.journal = dataManager;
this.inflightWrites = this.journal.getInflightWrites();
this.maxWriteBatchSize = this.journal.getWriteBatchSize();
}
/**
* @param type
* @param marshaller
* @param payload
* @param type
* @param sync
* @return
* @throws IOException
* @throws
* @throws
*/
public Location storeItem(ByteSequence data, byte type, boolean sync) throws IOException {
// Write the packet our internal buffer.
int size = data.getLength() + Journal.RECORD_HEAD_SPACE;
final Location location = new Location();
location.setSize(size);
location.setType(type);
WriteBatch batch;
WriteCommand write = new WriteCommand(location, data, sync);
// Locate datafile and enqueue into the executor in sychronized block so
// that writes get equeued onto the executor in order that they were
// assigned
// by the data manager (which is basically just appending)
synchronized (this) {
batch = enqueue(write);
}
location.setLatch(batch.latch);
if (sync) {
try {
batch.latch.await();
} catch (InterruptedException e) {
throw new InterruptedIOException();
}
IOException exception = batch.exception.get();
if (exception != null) {
throw exception;
}
}
return location;
}
public Location storeItem(ByteSequence data, byte type, Runnable onComplete) throws IOException {
// Write the packet our internal buffer.
int size = data.getLength() + Journal.RECORD_HEAD_SPACE;
final Location location = new Location();
location.setSize(size);
location.setType(type);
WriteBatch batch;
WriteCommand write = new WriteCommand(location, data, onComplete);
synchronized (this) {
batch = enqueue(write);
}
location.setLatch(batch.latch);
return location;
}
private WriteBatch enqueue(WriteCommand write) throws IOException {
synchronized (enqueueMutex) {
if (shutdown) {
throw new IOException("Async Writter Thread Shutdown");
}
if (!running) {
running = true;
thread = new Thread() {
public void run() {
processQueue();
}
};
thread.setPriority(Thread.MAX_PRIORITY);
thread.setDaemon(true);
thread.setName("ActiveMQ Data File Writer");
thread.start();
firstAsyncException = null;
}
if (firstAsyncException != null) {
throw firstAsyncException;
}
while ( true ) {
if (nextWriteBatch == null) {
DataFile file = journal.getCurrentWriteFile();
if( file.getLength() > journal.getMaxFileLength() ) {
file = journal.rotateWriteFile();
}
nextWriteBatch = new WriteBatch(file, file.getLength(), write);
enqueueMutex.notify();
break;
} else {
// Append to current batch if possible..
if (nextWriteBatch.canAppend(write)) {
nextWriteBatch.append(write);
break;
} else {
// Otherwise wait for the queuedCommand to be null
try {
while (nextWriteBatch != null) {
enqueueMutex.wait();
}
} catch (InterruptedException e) {
throw new InterruptedIOException();
}
if (shutdown) {
throw new IOException("Async Writter Thread Shutdown");
}
}
}
}
if (!write.sync) {
inflightWrites.put(new WriteKey(write.location), write);
}
return nextWriteBatch;
}
}
public void close() throws IOException {
synchronized (enqueueMutex) {
if (!shutdown) {
shutdown = true;
if (running) {
enqueueMutex.notifyAll();
} else {
shutdownDone.countDown();
}
}
}
try {
shutdownDone.await();
} catch (InterruptedException e) {
throw new InterruptedIOException();
}
}
/**
* The async processing loop that writes to the data files and does the
* force calls. Since the file sync() call is the slowest of all the
* operations, this algorithm tries to 'batch' or group together several
* file sync() requests into a single file sync() call. The batching is
* accomplished attaching the same CountDownLatch instance to every force
* request in a group.
*/
protected void processQueue() {
DataFile dataFile = null;
RandomAccessFile file = null;
WriteBatch wb = null;
try {
DataByteArrayOutputStream buff = new DataByteArrayOutputStream(maxWriteBatchSize);
while (true) {
Object o = null;
// Block till we get a command.
synchronized (enqueueMutex) {
while (true) {
if (nextWriteBatch != null) {
o = nextWriteBatch;
nextWriteBatch = null;
break;
}
if (shutdown) {
return;
}
enqueueMutex.wait();
}
enqueueMutex.notify();
}
wb = (WriteBatch)o;
if (dataFile != wb.dataFile) {
if (file != null) {
file.setLength(dataFile.getLength());
dataFile.closeRandomAccessFile(file);
}
dataFile = wb.dataFile;
file = dataFile.openRandomAccessFile();
if( file.length() < journal.preferedFileLength ) {
file.setLength(journal.preferedFileLength);
}
}
WriteCommand write = wb.writes.getHead();
// Write an empty batch control record.
buff.reset();
buff.writeInt(Journal.BATCH_CONTROL_RECORD_SIZE);
buff.writeByte(Journal.BATCH_CONTROL_RECORD_TYPE);
buff.write(Journal.BATCH_CONTROL_RECORD_MAGIC);
buff.writeInt(0);
buff.writeLong(0);
boolean forceToDisk = false;
while (write != null) {
forceToDisk |= write.sync | write.onComplete != null;
buff.writeInt(write.location.getSize());
buff.writeByte(write.location.getType());
buff.write(write.data.getData(), write.data.getOffset(), write.data.getLength());
write = write.getNext();
}
ByteSequence sequence = buff.toByteSequence();
// Now we can fill in the batch control record properly.
buff.reset();
buff.skip(5+Journal.BATCH_CONTROL_RECORD_MAGIC.length);
buff.writeInt(sequence.getLength()-Journal.BATCH_CONTROL_RECORD_SIZE);
if( journal.isChecksum() ) {
Checksum checksum = new Adler32();
checksum.update(sequence.getData(), sequence.getOffset()+Journal.BATCH_CONTROL_RECORD_SIZE, sequence.getLength()-Journal.BATCH_CONTROL_RECORD_SIZE);
buff.writeLong(checksum.getValue());
}
// Now do the 1 big write.
file.seek(wb.offset);
file.write(sequence.getData(), sequence.getOffset(), sequence.getLength());
ReplicationTarget replicationTarget = journal.getReplicationTarget();
if( replicationTarget!=null ) {
replicationTarget.replicate(wb.writes.getHead().location, sequence, forceToDisk);
}
if (forceToDisk) {
file.getFD().sync();
}
WriteCommand lastWrite = wb.writes.getTail();
journal.setLastAppendLocation(lastWrite.location);
// Now that the data is on disk, remove the writes from the in
// flight
// cache.
write = wb.writes.getHead();
while (write != null) {
if (!write.sync) {
inflightWrites.remove(new WriteKey(write.location));
}
if (write.onComplete != null) {
try {
write.onComplete.run();
} catch (Throwable e) {
e.printStackTrace();
}
}
write = write.getNext();
}
// Signal any waiting threads that the write is on disk.
wb.latch.countDown();
}
} catch (IOException e) {
synchronized (enqueueMutex) {
firstAsyncException = e;
if (wb != null) {
wb.latch.countDown();
wb.exception.set(e);
}
if (nextWriteBatch != null) {
nextWriteBatch.latch.countDown();
nextWriteBatch.exception.set(e);
}
}
} catch (InterruptedException e) {
} finally {
try {
if (file != null) {
dataFile.closeRandomAccessFile(file);
}
} catch (Throwable ignore) {
}
shutdownDone.countDown();
running = false;
}
}
}