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Server functionality for HBase
/**
* 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.Closeable;
import java.io.IOException;
import java.net.ConnectException;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.Abortable;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.regionserver.wal.AbstractFSWAL;
import org.apache.hadoop.hbase.regionserver.wal.FailedLogCloseException;
import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.ipc.RemoteException;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Runs periodically to determine if the WAL should be rolled.
*
* NOTE: This class extends Thread rather than Chore because the sleep time can be interrupted when
* there is something to do, rather than the Chore sleep time which is invariant.
*
* The {@link #scheduleFlush(String, List)} is abstract here,
* as sometimes we hold a region without a region server but we still want to roll its WAL.
*
* TODO: change to a pool of threads
*/
@InterfaceAudience.Private
public abstract class AbstractWALRoller extends Thread
implements Closeable {
private static final Logger LOG = LoggerFactory.getLogger(AbstractWALRoller.class);
protected static final String WAL_ROLL_PERIOD_KEY = "hbase.regionserver.logroll.period";
protected final ConcurrentMap wals = new ConcurrentHashMap<>();
protected final T abortable;
// Period to roll log.
private final long rollPeriod;
private final int threadWakeFrequency;
// The interval to check low replication on hlog's pipeline
private final long checkLowReplicationInterval;
private volatile boolean running = true;
public void addWAL(WAL wal) {
// check without lock first
if (wals.containsKey(wal)) {
return;
}
// this is to avoid race between addWAL and requestRollAll.
synchronized (this) {
if (wals.putIfAbsent(wal, new RollController(wal)) == null) {
wal.registerWALActionsListener(new WALActionsListener() {
@Override
public void logRollRequested(WALActionsListener.RollRequestReason reason) {
// TODO logs will contend with each other here, replace with e.g. DelayedQueue
synchronized (AbstractWALRoller.this) {
RollController controller = wals.computeIfAbsent(wal, rc -> new RollController(wal));
controller.requestRoll();
AbstractWALRoller.this.notifyAll();
}
}
@Override
public void postLogArchive(Path oldPath, Path newPath) throws IOException {
afterWALArchive(oldPath, newPath);
}
});
}
}
}
public void requestRollAll() {
synchronized (this) {
for (RollController controller : wals.values()) {
controller.requestRoll();
}
notifyAll();
}
}
protected AbstractWALRoller(String name, Configuration conf, T abortable) {
super(name);
this.abortable = abortable;
this.rollPeriod = conf.getLong(WAL_ROLL_PERIOD_KEY, 3600000);
this.threadWakeFrequency = conf.getInt(HConstants.THREAD_WAKE_FREQUENCY, 10 * 1000);
this.checkLowReplicationInterval =
conf.getLong("hbase.regionserver.hlog.check.lowreplication.interval", 30 * 1000);
}
/**
* we need to check low replication in period, see HBASE-18132
*/
private void checkLowReplication(long now) {
try {
for (Entry entry : wals.entrySet()) {
WAL wal = entry.getKey();
boolean needRollAlready = entry.getValue().needsRoll(now);
if (needRollAlready || !(wal instanceof AbstractFSWAL)) {
continue;
}
((AbstractFSWAL) wal).checkLogLowReplication(checkLowReplicationInterval);
}
} catch (Throwable e) {
LOG.warn("Failed checking low replication", e);
}
}
private void abort(String reason, Throwable cause) {
// close all WALs before calling abort on RS.
// This is because AsyncFSWAL replies on us for rolling a new writer to make progress, and if we
// failed, AsyncFSWAL may be stuck, so we need to close it to let the upper layer know that it
// is already broken.
for (WAL wal : wals.keySet()) {
// shutdown rather than close here since we are going to abort the RS and the wals need to be
// split when recovery
try {
wal.shutdown();
} catch (IOException e) {
LOG.warn("Failed to shutdown wal", e);
}
}
abortable.abort(reason, cause);
}
@Override
public void run() {
while (running) {
long now = System.currentTimeMillis();
checkLowReplication(now);
synchronized (this) {
if (wals.values().stream().noneMatch(rc -> rc.needsRoll(now))) {
try {
wait(this.threadWakeFrequency);
} catch (InterruptedException e) {
// restore the interrupt state
Thread.currentThread().interrupt();
}
// goto the beginning to check whether again whether we should fall through to roll
// several WALs, and also check whether we should quit.
continue;
}
}
try {
for (Iterator> iter = wals.entrySet().iterator();
iter.hasNext();) {
Entry entry = iter.next();
WAL wal = entry.getKey();
RollController controller = entry.getValue();
if (controller.isRollRequested()) {
// WAL roll requested, fall through
LOG.debug("WAL {} roll requested", wal);
} else if (controller.needsPeriodicRoll(now)) {
// Time for periodic roll, fall through
LOG.debug("WAL {} roll period {} ms elapsed", wal, this.rollPeriod);
} else {
continue;
}
// Force the roll if the logroll.period is elapsed or if a roll was requested.
// The returned value is an collection of actual region and family names.
Map> regionsToFlush = controller.rollWal(now);
if (regionsToFlush != null) {
for (Map.Entry> r : regionsToFlush.entrySet()) {
scheduleFlush(Bytes.toString(r.getKey()), r.getValue());
}
}
}
} catch (FailedLogCloseException | ConnectException e) {
abort("Failed log close in log roller", e);
} catch (IOException ex) {
// Abort if we get here. We probably won't recover an IOE. HBASE-1132
abort("IOE in log roller",
ex instanceof RemoteException ? ((RemoteException) ex).unwrapRemoteException() : ex);
} catch (Exception ex) {
LOG.error("Log rolling failed", ex);
abort("Log rolling failed", ex);
}
}
LOG.info("LogRoller exiting.");
}
protected void afterWALArchive(Path oldPath, Path newPath) {
}
/**
* @param encodedRegionName Encoded name of region to flush.
* @param families stores of region to flush.
*/
protected abstract void scheduleFlush(String encodedRegionName, List families);
private boolean isWaiting() {
Thread.State state = getState();
return state == Thread.State.WAITING || state == Thread.State.TIMED_WAITING;
}
/**
* @return true if all WAL roll finished
*/
public boolean walRollFinished() {
return wals.values().stream().noneMatch(rc -> rc.needsRoll(System.currentTimeMillis()))
&& isWaiting();
}
/**
* Wait until all wals have been rolled after calling {@link #requestRollAll()}.
*/
public void waitUntilWalRollFinished() throws InterruptedException {
while (!walRollFinished()) {
Thread.sleep(100);
}
}
@Override
public void close() {
running = false;
interrupt();
}
/**
* Independently control the roll of each wal. When use multiwal,
* can avoid all wal roll together. see HBASE-24665 for detail
*/
protected class RollController {
private final WAL wal;
private final AtomicBoolean rollRequest;
private long lastRollTime;
RollController(WAL wal) {
this.wal = wal;
this.rollRequest = new AtomicBoolean(false);
this.lastRollTime = System.currentTimeMillis();
}
public void requestRoll() {
this.rollRequest.set(true);
}
public Map> rollWal(long now) throws IOException {
this.lastRollTime = now;
// reset the flag in front to avoid missing roll request before we return from rollWriter.
this.rollRequest.set(false);
return wal.rollWriter(true);
}
public boolean isRollRequested() {
return rollRequest.get();
}
public boolean needsPeriodicRoll(long now) {
return (now - this.lastRollTime) > rollPeriod;
}
public boolean needsRoll(long now) {
return isRollRequested() || needsPeriodicRoll(now);
}
}
}