/**
* Copyright 2009 The Apache Software Foundation 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.hadoop.hbase.regionserver.transactional;
import java.io.IOException;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.regionserver.transactional.TransactionState.WriteAction;
import org.apache.hadoop.hbase.regionserver.wal.HLog;
import org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader;
import org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogWriter;
import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener;
import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
/**
* Add support for transactional operations to the regionserver's
* write-ahead-log.
*/
public class THLog extends HLog {
static final String THLOG_DATFILE = "thlog.dat.";
/** Name of old log file for reconstruction */
static final String HREGION_OLD_THLOGFILE_NAME = "oldthlogfile.log";
public THLog(final FileSystem fs, final Path dir, final Path oldLogDir,
final Configuration conf, final List<WALActionsListener> listeners)
throws IOException {
super(fs, dir, oldLogDir, conf, listeners, false, null);
}
/**
* Get a writer for the WAL.
*
* @param path
* @param conf
* @return A WAL writer. Close when done with it.
* @throws IOException
*/
public static Writer createWriter(final FileSystem fs, final Path path,
final Configuration conf) throws IOException {
try {
HLog.Writer writer = new SequenceFileLogWriter(THLogKey.class);
writer.init(fs, path, conf);
return writer;
} catch (Exception e) {
IOException ie = new IOException("cannot get log writer");
ie.initCause(e);
throw ie;
}
}
@Override
protected Writer createWriterInstance(final FileSystem fs, final Path path,
final Configuration conf) throws IOException {
return createWriter(fs, path, conf);
}
/**
* This is a convenience method that computes a new filename with a given
* file-number.
*
* @param fn
* @return Path
*/
@Override
protected Path computeFilename() {
// REVIEW : Use prefix ?
return new Path(getDir(), THLOG_DATFILE + getFilenum());
}
/**
* Get a reader for the WAL.
*
* @param fs
* @param path
* @param conf
* @return A WAL reader. Close when done with it.
* @throws IOException
*/
public static Reader getReader(final FileSystem fs, final Path path,
final Configuration conf) throws IOException {
try {
HLog.Reader reader = new SequenceFileLogReader(THLogKey.class);
reader.init(fs, path, conf);
return reader;
} catch (Exception e) {
IOException ie = new IOException("cannot get log reader");
ie.initCause(e);
throw ie;
}
}
protected THLogKey makeKey(final byte[] regionName, final byte[] tableName,
final long seqnum, final long now) {
return new THLogKey(regionName, tableName, seqnum, now, null, -1);
}
/**
* Write a transactional state to the log after we have decide that it can
* be committed. At this time we are still waiting for the final vote (from
* other regions), so the commit may not be processed.
*/
public void writeCommitResuestToLog(final HRegionInfo regionInfo,
final TransactionState transactionState) throws IOException {
this.appendCommitRequest(regionInfo,
EnvironmentEdgeManager.currentTimeMillis(), transactionState);
}
/**
* @param regionInfo
* @param transactionId
* @throws IOException
*/
public void writeCommitToLog(final HRegionInfo regionInfo,
final long transactionId) throws IOException {
this.append(regionInfo, EnvironmentEdgeManager.currentTimeMillis(),
THLogKey.TrxOp.COMMIT, transactionId);
}
/**
* @param regionInfo
* @param transactionId
* @throws IOException
*/
public void writeAbortToLog(final HRegionInfo regionInfo,
final long transactionId) throws IOException {
this.append(regionInfo, EnvironmentEdgeManager.currentTimeMillis(),
THLogKey.TrxOp.ABORT, transactionId);
}
/**
* Write a general transaction op to the log. This covers: start, commit,
* and abort.
*
* @param regionInfo
* @param now
* @param txOp
* @param transactionId
* @throws IOException
*/
private void append(final HRegionInfo regionInfo, final long now,
final THLogKey.TrxOp txOp, final long transactionId)
throws IOException {
@SuppressWarnings("deprecation")
THLogKey key = new THLogKey(regionInfo.getRegionName(), regionInfo
.getTableDesc().getName(), -1, now, txOp, transactionId);
WALEdit e = new WALEdit();
e.add(new KeyValue(new byte[0], 0, 0)); // Empty KeyValue
super.append(regionInfo, key, e, null, false);
}
/**
* Write a transactional state to the log for a commit request.
*
* @param regionInfo
* @param update
* @param transactionId
* @throws IOException
*/
private void appendCommitRequest(final HRegionInfo regionInfo,
final long now, final TransactionState transactionState)
throws IOException {
@SuppressWarnings("deprecation")
THLogKey key = new THLogKey(regionInfo.getRegionName(), regionInfo
.getTableDesc().getName(), -1, now,
THLogKey.TrxOp.COMMIT_REQUEST,
transactionState.getTransactionId());
WALEdit e = new WALEdit();
for (WriteAction write : transactionState.getWriteOrdering()) {
for (KeyValue value : write.getKeyValues()) {
e.add(value);
}
}
super.append(regionInfo, key, e, null, false);
}
}
