/**
* 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.Comparator;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
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.hbase.util.BoundedPriorityBlockingQueue;
import org.apache.hadoop.hbase.util.ReflectionUtils;
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;
public static final String CALL_QUEUE_HANDLER_FACTOR_CONF_KEY = "hbase.ipc.server.callqueue.handler.factor";
/** max delay in msec used to bound the deprioritized requests */
public static final String QUEUE_MAX_CALL_DELAY_CONF_KEY = "hbase.ipc.server.queue.max.call.delay";
/**
* The default, 'fifo', has the least friction but is dumb. If set to 'deadline', uses a priority
* queue and deprioritizes long-running scans. Sorting by priority comes at a cost, reduced
* throughput.
*/
public static final String CALL_QUEUE_TYPE_CODEL_CONF_VALUE = "codel";
public static final String CALL_QUEUE_TYPE_DEADLINE_CONF_VALUE = "deadline";
public static final String CALL_QUEUE_TYPE_FIFO_CONF_VALUE = "fifo";
public static final String CALL_QUEUE_TYPE_CONF_KEY = "hbase.ipc.server.callqueue.type";
public static final String CALL_QUEUE_TYPE_CONF_DEFAULT = CALL_QUEUE_TYPE_FIFO_CONF_VALUE;
// These 3 are only used by Codel executor
public static final String CALL_QUEUE_CODEL_TARGET_DELAY = "hbase.ipc.server.callqueue.codel.target.delay";
public static final String CALL_QUEUE_CODEL_INTERVAL = "hbase.ipc.server.callqueue.codel.interval";
public static final String CALL_QUEUE_CODEL_LIFO_THRESHOLD = "hbase.ipc.server.callqueue.codel.lifo.threshold";
public static final int CALL_QUEUE_CODEL_DEFAULT_TARGET_DELAY = 100;
public static final int CALL_QUEUE_CODEL_DEFAULT_INTERVAL = 100;
public static final double CALL_QUEUE_CODEL_DEFAULT_LIFO_THRESHOLD = 0.8;
private AtomicLong numGeneralCallsDropped = new AtomicLong();
private AtomicLong numLifoModeSwitches = new AtomicLong();
protected final int numCallQueues;
protected final List<BlockingQueue<CallRunner>> queues;
private final Class<? extends BlockingQueue> queueClass;
private final Object[] queueInitArgs;
private final PriorityFunction priority;
protected volatile int currentQueueLimit;
private final AtomicInteger activeHandlerCount = new AtomicInteger(0);
private final List<Handler> handlers;
private final int handlerCount;
private final AtomicInteger failedHandlerCount = new AtomicInteger(0);
private String name;
private boolean running;
private Configuration conf = null;
private Abortable abortable = null;
public RpcExecutor(final String name, final int handlerCount, final int maxQueueLength,
final PriorityFunction priority, final Configuration conf, final Abortable abortable) {
this(name, handlerCount, conf.get(CALL_QUEUE_TYPE_CONF_KEY,
CALL_QUEUE_TYPE_CONF_DEFAULT), maxQueueLength, priority, conf, abortable);
}
public RpcExecutor(final String name, final int handlerCount, final String callQueueType,
final int maxQueueLength, final PriorityFunction priority, final Configuration conf,
final Abortable abortable) {
this.name = Strings.nullToEmpty(name);
this.conf = conf;
this.abortable = abortable;
float callQueuesHandlersFactor = this.conf.getFloat(CALL_QUEUE_HANDLER_FACTOR_CONF_KEY, 0);
this.numCallQueues = computeNumCallQueues(handlerCount, callQueuesHandlersFactor);
this.queues = new ArrayList<>(this.numCallQueues);
this.handlerCount = Math.max(handlerCount, this.numCallQueues);
this.handlers = new ArrayList<>(this.handlerCount);
this.priority = priority;
if (isDeadlineQueueType(callQueueType)) {
this.name += ".Deadline";
this.queueInitArgs = new Object[] { maxQueueLength,
new CallPriorityComparator(conf, this.priority) };
this.queueClass = BoundedPriorityBlockingQueue.class;
} else if (isCodelQueueType(callQueueType)) {
this.name += ".Codel";
int codelTargetDelay = conf.getInt(CALL_QUEUE_CODEL_TARGET_DELAY,
CALL_QUEUE_CODEL_DEFAULT_TARGET_DELAY);
int codelInterval = conf.getInt(CALL_QUEUE_CODEL_INTERVAL, CALL_QUEUE_CODEL_DEFAULT_INTERVAL);
double codelLifoThreshold = conf.getDouble(CALL_QUEUE_CODEL_LIFO_THRESHOLD,
CALL_QUEUE_CODEL_DEFAULT_LIFO_THRESHOLD);
queueInitArgs = new Object[] { maxQueueLength, codelTargetDelay, codelInterval,
codelLifoThreshold, numGeneralCallsDropped, numLifoModeSwitches };
queueClass = AdaptiveLifoCoDelCallQueue.class;
} else {
this.name += ".Fifo";
queueInitArgs = new Object[] { maxQueueLength };
queueClass = LinkedBlockingQueue.class;
}
LOG.info("RpcExecutor " + " name " + " using " + callQueueType
+ " as call queue; numCallQueues=" + numCallQueues + "; maxQueueLength=" + maxQueueLength
+ "; handlerCount=" + handlerCount);
}
protected int computeNumCallQueues(final int handlerCount, final float callQueuesHandlersFactor) {
return Math.max(1, (int) Math.round(handlerCount * callQueuesHandlersFactor));
}
protected void initializeQueues(final int numQueues) {
if (queueInitArgs.length > 0) {
currentQueueLimit = (int) queueInitArgs[0];
queueInitArgs[0] = Math.max((int) queueInitArgs[0], DEFAULT_CALL_QUEUE_SIZE_HARD_LIMIT);
}
for (int i = 0; i < numQueues; ++i) {
queues
.add((BlockingQueue<CallRunner>) ReflectionUtils.newInstance(queueClass, queueInitArgs));
}
}
public void start(final int port) {
running = true;
startHandlers(port);
}
public void stop() {
running = false;
for (Thread handler : handlers) {
handler.interrupt();
}
}
/** Add the request to the executor queue */
public abstract boolean dispatch(final CallRunner callTask) throws InterruptedException;
/** Returns the list of request queues */
protected List<BlockingQueue<CallRunner>> getQueues() {
return queues;
}
protected void startHandlers(final int port) {
List<BlockingQueue<CallRunner>> callQueues = getQueues();
startHandlers(null, handlerCount, callQueues, 0, callQueues.size(), port, activeHandlerCount);
}
/**
* Override if providing alternate Handler implementation.
*/
protected Handler getHandler(final String name, final double handlerFailureThreshhold,
final BlockingQueue<CallRunner> q, final AtomicInteger activeHandlerCount) {
return new Handler(name, handlerFailureThreshhold, q, activeHandlerCount);
}
/**
* Start up our handlers.
*/
protected void startHandlers(final String nameSuffix, final int numHandlers,
final List<BlockingQueue<CallRunner>> callQueues, final int qindex, final int qsize,
final int port, final AtomicInteger activeHandlerCount) {
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),
activeHandlerCount);
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<CallRunner> q;
final double handlerFailureThreshhold;
// metrics (shared with other handlers)
final AtomicInteger activeHandlerCount;
Handler(final String name, final double handlerFailureThreshhold,
final BlockingQueue<CallRunner> q, final AtomicInteger activeHandlerCount) {
super(name);
setDaemon(true);
this.q = q;
this.handlerFailureThreshhold = handlerFailureThreshhold;
this.activeHandlerCount = activeHandlerCount;
}
/**
* @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 {
this.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 {
this.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);
}
}
/**
* Comparator used by the "normal callQueue" if DEADLINE_CALL_QUEUE_CONF_KEY is set to true. It
* uses the calculated "deadline" e.g. to deprioritize long-running job If multiple requests have
* the same deadline BoundedPriorityBlockingQueue will order them in FIFO (first-in-first-out)
* manner.
*/
private static class CallPriorityComparator implements Comparator<CallRunner> {
private final static int DEFAULT_MAX_CALL_DELAY = 5000;
private final PriorityFunction priority;
private final int maxDelay;
public CallPriorityComparator(final Configuration conf, final PriorityFunction priority) {
this.priority = priority;
this.maxDelay = conf.getInt(QUEUE_MAX_CALL_DELAY_CONF_KEY, DEFAULT_MAX_CALL_DELAY);
}
@Override
public int compare(CallRunner a, CallRunner b) {
RpcCall callA = a.getRpcCall();
RpcCall callB = b.getRpcCall();
long deadlineA = priority.getDeadline(callA.getHeader(), callA.getParam());
long deadlineB = priority.getDeadline(callB.getHeader(), callB.getParam());
deadlineA = callA.getReceiveTime() + Math.min(deadlineA, maxDelay);
deadlineB = callB.getReceiveTime() + Math.min(deadlineB, maxDelay);
return Long.compare(deadlineA, deadlineB);
}
}
public static boolean isDeadlineQueueType(final String callQueueType) {
return callQueueType.equals(CALL_QUEUE_TYPE_DEADLINE_CONF_VALUE);
}
public static boolean isCodelQueueType(final String callQueueType) {
return callQueueType.equals(CALL_QUEUE_TYPE_CODEL_CONF_VALUE);
}
public static boolean isFifoQueueType(final String callQueueType) {
return callQueueType.equals(CALL_QUEUE_TYPE_FIFO_CONF_VALUE);
}
public long getNumGeneralCallsDropped() {
return numGeneralCallsDropped.get();
}
public long getNumLifoModeSwitches() {
return numLifoModeSwitches.get();
}
public int getActiveHandlerCount() {
return activeHandlerCount.get();
}
public int getActiveWriteHandlerCount() {
return 0;
}
public int getActiveReadHandlerCount() {
return 0;
}
public int getActiveScanHandlerCount() {
return 0;
}
/** Returns the length of the pending queue */
public int getQueueLength() {
int length = 0;
for (final BlockingQueue<CallRunner> queue: queues) {
length += queue.size();
}
return length;
}
public int getReadQueueLength() {
return 0;
}
public int getScanQueueLength() {
return 0;
}
public int getWriteQueueLength() {
return 0;
}
public String getName() {
return this.name;
}
/**
* 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(Locale.ROOT).contains("priority")) {
configKey = RpcScheduler.IPC_SERVER_PRIORITY_MAX_CALLQUEUE_LENGTH;
}
currentQueueLimit = conf.getInt(configKey, currentQueueLimit);
}
public void onConfigurationChange(Configuration conf) {
// update CoDel Scheduler tunables
int codelTargetDelay = conf.getInt(CALL_QUEUE_CODEL_TARGET_DELAY,
CALL_QUEUE_CODEL_DEFAULT_TARGET_DELAY);
int codelInterval = conf.getInt(CALL_QUEUE_CODEL_INTERVAL, CALL_QUEUE_CODEL_DEFAULT_INTERVAL);
double codelLifoThreshold = conf.getDouble(CALL_QUEUE_CODEL_LIFO_THRESHOLD,
CALL_QUEUE_CODEL_DEFAULT_LIFO_THRESHOLD);
for (BlockingQueue<CallRunner> queue : queues) {
if (queue instanceof AdaptiveLifoCoDelCallQueue) {
((AdaptiveLifoCoDelCallQueue) queue).updateTunables(codelTargetDelay, codelInterval,
codelLifoThreshold);
}
}
}
}