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Apache Geode provides a database-like consistency model, reliable transaction processing and a shared-nothing architecture to maintain very low latency performance with high concurrency processing
/*
* 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.geode.cache.server.internal;
import java.util.ArrayList;
import java.util.Set;
import org.apache.logging.log4j.Logger;
import org.apache.geode.CancelException;
import org.apache.geode.SystemFailure;
import org.apache.geode.cache.client.internal.CacheServerLoadMessage;
import org.apache.geode.cache.server.ServerLoad;
import org.apache.geode.cache.server.ServerLoadProbe;
import org.apache.geode.distributed.internal.ServerLocation;
import org.apache.geode.distributed.internal.membership.MembershipManager;
import org.apache.geode.internal.cache.CacheServerAdvisor;
import org.apache.geode.internal.cache.tier.Acceptor;
import org.apache.geode.internal.cache.tier.sockets.CacheServerStats;
import org.apache.geode.internal.cache.tier.sockets.ClientProxyMembershipID;
import org.apache.geode.internal.cache.tier.sockets.ConnectionListener;
import org.apache.geode.internal.i18n.LocalizedStrings;
import org.apache.geode.internal.logging.LogService;
import org.apache.geode.internal.logging.log4j.LocalizedMessage;
/**
* A class which monitors the load on a bridge server and periodically sends updates to the locator.
*
* @since GemFire 5.7
*
*/
public class LoadMonitor implements ConnectionListener {
private static final Logger logger = LogService.getLogger();
private final ServerLoadProbe probe;
private final ServerMetricsImpl metrics;
protected final CacheServerAdvisor advisor;
protected ServerLocation location;
private final PollingThread pollingThread;
protected volatile ServerLoad lastLoad;
protected CacheServerStats stats;
public LoadMonitor(ServerLoadProbe probe, int maxConnections, long pollInterval,
int forceUpdateFrequency, CacheServerAdvisor advisor) {
this.probe = probe;
this.metrics = new ServerMetricsImpl(maxConnections);
this.pollingThread = new PollingThread(pollInterval, forceUpdateFrequency);
lastLoad = getLoad();
this.advisor = advisor;
}
/**
* Start the load monitor. Starts the background thread which polls the load monitor and sends
* updates about load.
*/
public void start(ServerLocation location, CacheServerStats cacheServerStats) {
probe.open();
this.location = location;
this.pollingThread.start();
this.stats = cacheServerStats;
this.stats.setLoad(lastLoad);
}
/**
* Stops the load monitor
*/
public void stop() {
this.pollingThread.close();
try {
this.pollingThread.join(5000);
} catch (InterruptedException e) {
logger.warn(LocalizedMessage
.create(LocalizedStrings.LoadMonitor_INTERRUPTED_WAITING_FOR_POLLING_THREAD_TO_FINISH));
Thread.currentThread().interrupt();
}
probe.close();
}
public void connectionClosed(boolean lastConnection, byte communicationMode) {
if (communicationMode == Acceptor.CLIENT_TO_SERVER) {
metrics.decConnectionCount();
}
if (lastConnection) {
metrics.decClientCount();
}
}
public ServerLoad getLastLoad() {
return lastLoad;
}
public void connectionOpened(boolean firstConnection, byte communicationMode) {
// ignore all other types of client connections.
if (communicationMode == Acceptor.CLIENT_TO_SERVER) {
metrics.incConnectionCount();
}
if (firstConnection) {
metrics.incClientCount();
}
}
/**
* Keeps track of the clients that have added a queue since the last load was sent to the
* server-locator.
*
* @since GemFire 5.7
*/
protected final ArrayList clientIds = new ArrayList();
public void queueAdded(ClientProxyMembershipID id) {
synchronized (this.clientIds) {
metrics.incQueueCount();
this.clientIds.add(id);
}
}
public void queueRemoved() {
metrics.decQueueCount();
}
protected ServerLoad getLoad() {
ServerLoad load = this.probe.getLoad(metrics);
if (load == null) {
load = new ServerLoad();
}
return load;
}
private class PollingThread extends Thread {
private final Object signal = new Object();
private final long pollInterval;
private volatile boolean alive = true;
private final int forceUpdateFrequency;
private int skippedLoadUpdates;
public PollingThread(long pollInterval, int forceUpdateFrequency) {
super("Cache Server Load Polling Thread");
this.pollInterval = pollInterval;
this.forceUpdateFrequency = forceUpdateFrequency;
this.setDaemon(true);
}
public void close() {
alive = false;
synchronized (signal) {
signal.notifyAll();
}
}
@Override
public void run() {
while (alive) {
try {
synchronized (signal) {
long end = System.currentTimeMillis() + pollInterval;
long remaining = pollInterval;
while (alive && remaining > 0) {
signal.wait(remaining);
remaining = end - System.currentTimeMillis();
}
}
if (!alive) {
return;
}
ServerLoad previousLoad = lastLoad;
ArrayList myClientIds = null;
ServerLoad load = null;
synchronized (clientIds) {
if (!clientIds.isEmpty()) {
myClientIds = new ArrayList(clientIds);
clientIds.clear();
}
load = getLoad();
}
lastLoad = load;
// don't send a message if the load hasn't
// changed, unless we have waited too long
// since the last update.
if (!previousLoad.equals(load) || myClientIds != null
|| ++skippedLoadUpdates > forceUpdateFrequency) {
Set locators = advisor.adviseControllers();
if (logger.isDebugEnabled()) {
logger.debug("Bridge Server Load Monitor Transmitting load {} to locators {}", load,
locators);
}
stats.setLoad(load);
if (locators != null) {
CacheServerLoadMessage message =
new CacheServerLoadMessage(load, location, myClientIds);
message.setRecipients(locators);
MembershipManager mgr = advisor.getDistributionManager().getMembershipManager();
if (mgr == null || !mgr.isBeingSick()) { // test hook
advisor.getDistributionManager().putOutgoing(message);
}
// Update any local locators
message.updateLocalLocators();
}
skippedLoadUpdates = 0;
} else {
if (logger.isDebugEnabled()) {
logger.debug(
"Bridge Server Load Monitor Load {} hasn't changed, not transmitting. skippedLoadUpdates={}",
load, skippedLoadUpdates);
}
}
} catch (InterruptedException e) {
SystemFailure.checkFailure();
} catch (VirtualMachineError e) {
SystemFailure.initiateFailure(e);
throw e;
} catch (CancelException e) {
return;
} catch (Throwable t) {
SystemFailure.checkFailure();
logger.warn(
LocalizedMessage.create(
LocalizedStrings.LoadMonitor_CACHESERVER_LOAD_MONITOR_ERROR_IN_POLLING_THREAD),
t);
}
} // while
}
}
}