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Main 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.ipc;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Abortable;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.monitoring.MonitoredRPCHandler;
import org.apache.hadoop.util.StringUtils;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
/**
* Runs the CallRunners passed here via {@link #dispatch(CallRunner)}. Subclass and add particular
* scheduling behavior.
*/
@InterfaceAudience.Private
public abstract class RpcExecutor {
private static final Log LOG = LogFactory.getLog(RpcExecutor.class);
protected static final int DEFAULT_CALL_QUEUE_SIZE_HARD_LIMIT = 250;
protected volatile int currentQueueLimit;
private final AtomicInteger activeHandlerCount = new AtomicInteger(0);
private final List handlers;
private final int handlerCount;
private final String name;
private final AtomicInteger failedHandlerCount = new AtomicInteger(0);
private boolean running;
private Configuration conf = null;
private Abortable abortable = null;
public RpcExecutor(final String name, final int handlerCount) {
this.handlers = new ArrayList(handlerCount);
this.handlerCount = handlerCount;
this.name = Strings.nullToEmpty(name);
}
public RpcExecutor(final String name, final int handlerCount, final Configuration conf,
final Abortable abortable) {
this(name, handlerCount);
this.conf = conf;
this.abortable = abortable;
}
public void start(final int port) {
running = true;
startHandlers(port);
}
public void stop() {
running = false;
for (Thread handler : handlers) {
handler.interrupt();
}
}
public int getActiveHandlerCount() {
return activeHandlerCount.get();
}
/** Returns the length of the pending queue */
public abstract int getQueueLength();
/** Add the request to the executor queue */
public abstract boolean dispatch(final CallRunner callTask) throws InterruptedException;
/** Returns the list of request queues */
protected abstract List> getQueues();
protected void startHandlers(final int port) {
List> callQueues = getQueues();
startHandlers(null, handlerCount, callQueues, 0, callQueues.size(), port);
}
/**
* Override if providing alternate Handler implementation.
*/
protected Handler getHandler(final String name, final double handlerFailureThreshhold,
final BlockingQueue q) {
return new Handler(name, handlerFailureThreshhold, q);
}
/**
* Start up our handlers.
*/
protected void startHandlers(final String nameSuffix, final int numHandlers,
final List> callQueues,
final int qindex, final int qsize, final int port) {
final String threadPrefix = name + Strings.nullToEmpty(nameSuffix);
double handlerFailureThreshhold =
conf == null ? 1.0 : conf.getDouble(HConstants.REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT,
HConstants.DEFAULT_REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT);
for (int i = 0; i < numHandlers; i++) {
final int index = qindex + (i % qsize);
String name = "RpcServer." + threadPrefix + ".handler=" + handlers.size() + ",queue=" +
index + ",port=" + port;
Handler handler = getHandler(name, handlerFailureThreshhold, callQueues.get(index));
handler.start();
LOG.debug("Started " + name);
handlers.add(handler);
}
}
/**
* Handler thread run the {@link CallRunner#run()} in.
*/
protected class Handler extends Thread {
/**
* Q to find CallRunners to run in.
*/
final BlockingQueue q;
final double handlerFailureThreshhold;
Handler(final String name, final double handlerFailureThreshhold,
final BlockingQueue q) {
super(name);
setDaemon(true);
this.q = q;
this.handlerFailureThreshhold = handlerFailureThreshhold;
}
/**
* @return A {@link CallRunner}
* @throws InterruptedException
*/
protected CallRunner getCallRunner() throws InterruptedException {
return this.q.take();
}
@Override
public void run() {
boolean interrupted = false;
try {
while (running) {
try {
run(getCallRunner());
} catch (InterruptedException e) {
interrupted = true;
}
}
} catch (Exception e) {
LOG.warn(e);
throw e;
} finally {
if (interrupted) {
Thread.currentThread().interrupt();
}
}
}
private void run(CallRunner cr) {
MonitoredRPCHandler status = RpcServer.getStatus();
cr.setStatus(status);
try {
activeHandlerCount.incrementAndGet();
cr.run();
} catch (Throwable e) {
if (e instanceof Error) {
int failedCount = failedHandlerCount.incrementAndGet();
if (this.handlerFailureThreshhold >= 0 &&
failedCount > handlerCount * this.handlerFailureThreshhold) {
String message = "Number of failed RpcServer handler runs exceeded threshhold " +
this.handlerFailureThreshhold + "; reason: " + StringUtils.stringifyException(e);
if (abortable != null) {
abortable.abort(message, e);
} else {
LOG.error("Error but can't abort because abortable is null: " +
StringUtils.stringifyException(e));
throw e;
}
} else {
LOG.warn("Handler errors " + StringUtils.stringifyException(e));
}
} else {
LOG.warn("Handler exception " + StringUtils.stringifyException(e));
}
} finally {
activeHandlerCount.decrementAndGet();
}
}
}
public static abstract class QueueBalancer {
/**
* @return the index of the next queue to which a request should be inserted
*/
public abstract int getNextQueue();
}
public static QueueBalancer getBalancer(int queueSize) {
Preconditions.checkArgument(queueSize > 0, "Queue size is <= 0, must be at least 1");
if (queueSize == 1) {
return ONE_QUEUE;
} else {
return new RandomQueueBalancer(queueSize);
}
}
/**
* All requests go to the first queue, at index 0
*/
private static QueueBalancer ONE_QUEUE = new QueueBalancer() {
@Override
public int getNextQueue() {
return 0;
}
};
/**
* Queue balancer that just randomly selects a queue in the range [0, num queues).
*/
private static class RandomQueueBalancer extends QueueBalancer {
private final int queueSize;
public RandomQueueBalancer(int queueSize) {
this.queueSize = queueSize;
}
public int getNextQueue() {
return ThreadLocalRandom.current().nextInt(queueSize);
}
}
/**
* Update current soft limit for executor's call queues
* @param conf updated configuration
*/
public void resizeQueues(Configuration conf) {
String configKey = RpcScheduler.IPC_SERVER_MAX_CALLQUEUE_LENGTH;
if (name != null && name.toLowerCase().contains("priority")) {
configKey = RpcScheduler.IPC_SERVER_PRIORITY_MAX_CALLQUEUE_LENGTH;
}
currentQueueLimit = conf.getInt(configKey, currentQueueLimit);
}
}