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/**
* 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.wal;
import java.io.IOException;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
// imports for things that haven't moved from regionserver.wal yet.
import org.apache.hadoop.hbase.regionserver.MultiVersionConcurrencyControl.WriteEntry;
import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener;
import org.apache.hadoop.hbase.regionserver.wal.WALCoprocessorHost;
import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
import org.apache.hadoop.hbase.util.FSUtils;
/**
* No-op implementation of {@link WALProvider} used when the WAL is disabled.
*
* Should only be used when severe data loss is acceptable.
*
*/
@InterfaceAudience.Private
class DisabledWALProvider implements WALProvider {
private static final Log LOG = LogFactory.getLog(DisabledWALProvider.class);
WAL disabled;
@Override
public void init(final WALFactory factory, final Configuration conf,
final List listeners, String providerId) throws IOException {
if (null != disabled) {
throw new IllegalStateException("WALProvider.init should only be called once.");
}
if (null == providerId) {
providerId = "defaultDisabled";
}
disabled = new DisabledWAL(new Path(FSUtils.getRootDir(conf), providerId), conf, null);
}
@Override
public WAL getWAL(final byte[] identifier) throws IOException {
return disabled;
}
@Override
public void close() throws IOException {
disabled.close();
}
@Override
public void shutdown() throws IOException {
disabled.shutdown();
}
private static class DisabledWAL implements WAL {
protected final List listeners =
new CopyOnWriteArrayList();
protected final Path path;
protected final WALCoprocessorHost coprocessorHost;
protected final AtomicBoolean closed = new AtomicBoolean(false);
public DisabledWAL(final Path path, final Configuration conf,
final List listeners) {
this.coprocessorHost = new WALCoprocessorHost(this, conf);
this.path = path;
if (null != listeners) {
for(WALActionsListener listener : listeners) {
registerWALActionsListener(listener);
}
}
}
@Override
public void registerWALActionsListener(final WALActionsListener listener) {
listeners.add(listener);
}
@Override
public boolean unregisterWALActionsListener(final WALActionsListener listener) {
return listeners.remove(listener);
}
@Override
public byte[][] rollWriter() {
if (!listeners.isEmpty()) {
for (WALActionsListener listener : listeners) {
listener.logRollRequested(false);
}
for (WALActionsListener listener : listeners) {
try {
listener.preLogRoll(path, path);
} catch (IOException exception) {
LOG.debug("Ignoring exception from listener.", exception);
}
}
for (WALActionsListener listener : listeners) {
try {
listener.postLogRoll(path, path);
} catch (IOException exception) {
LOG.debug("Ignoring exception from listener.", exception);
}
}
}
return null;
}
@Override
public byte[][] rollWriter(boolean force) {
return rollWriter();
}
@Override
public void shutdown() {
if(closed.compareAndSet(false, true)) {
if (!this.listeners.isEmpty()) {
for (WALActionsListener listener : this.listeners) {
listener.logCloseRequested();
}
}
}
}
@Override
public void close() {
shutdown();
}
@Override
public long append(HTableDescriptor htd, HRegionInfo info, WALKey key, WALEdit edits,
boolean inMemstore) throws IOException {
WriteEntry writeEntry = key.getMvcc().begin();
if (!edits.isReplay()) {
for (Cell cell : edits.getCells()) {
CellUtil.setSequenceId(cell, writeEntry.getWriteNumber());
}
}
key.setWriteEntry(writeEntry);
if (!this.listeners.isEmpty()) {
final long start = System.nanoTime();
long len = 0;
for (Cell cell : edits.getCells()) {
len += CellUtil.estimatedSerializedSizeOf(cell);
}
final long elapsed = (System.nanoTime() - start)/1000000l;
for (WALActionsListener listener : this.listeners) {
listener.postAppend(len, elapsed);
}
}
return -1;
}
@Override
public void sync() {
if (!this.listeners.isEmpty()) {
for (WALActionsListener listener : this.listeners) {
listener.postSync(0l, 0);
}
}
}
@Override
public void sync(long txid) {
sync();
}
@Override
public Long startCacheFlush(final byte[] encodedRegionName, Set flushedFamilyNames) {
if (closed.get()) return null;
return HConstants.NO_SEQNUM;
}
@Override
public void completeCacheFlush(final byte[] encodedRegionName) {
}
@Override
public void abortCacheFlush(byte[] encodedRegionName) {
}
@Override
public WALCoprocessorHost getCoprocessorHost() {
return coprocessorHost;
}
@Override
public long getEarliestMemstoreSeqNum(byte[] encodedRegionName) {
return HConstants.NO_SEQNUM;
}
@Override
public long getEarliestMemstoreSeqNum(byte[] encodedRegionName, byte[] familyName) {
return HConstants.NO_SEQNUM;
}
@Override
public String toString() {
return "WAL disabled.";
}
}
}