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Posted to commits@hbase.apache.org by li...@apache.org on 2013/05/18 20:18:33 UTC
svn commit: r1484158 - in /hbase/branches/0.89-fb/src:
main/java/org/apache/hadoop/hbase/conf/
main/java/org/apache/hadoop/hbase/regionserver/
test/java/org/apache/hadoop/hbase/conf/
Author: liyin
Date: Sat May 18 18:18:32 2013
New Revision: 1484158
URL: http://svn.apache.org/r1484158
Log:
[HBASE-8576] Allow individual classes to get notified when Configuration is reloaded
Author: gauravm
Summary: As a part of online configuration update, we want to allow individual classes to listen for changes in certain configuration properties.
Test Plan: Unit Tests
Reviewers: liyintang, aaiyer, shaneh, rshroff, manukranthk, adela
Reviewed By: liyintang
CC: hbase-eng@
Differential Revision: https://phabricator.fb.com/D812768
Task ID: 2258346
Added:
hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/
hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationManager.java
hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationObserver.java
hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/conf/
hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/conf/TestConfigurationManager.java
Modified:
hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
Added: hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationManager.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationManager.java?rev=1484158&view=auto
==============================================================================
--- hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationManager.java (added)
+++ hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationManager.java Sat May 18 18:18:32 2013
@@ -0,0 +1,97 @@
+/**
+ * Copyright 2013 The Apache Software Foundation
+ *
+ * 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.conf;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.WeakHashMap;
+
+/**
+ * Maintains a set of all the classes which are would like to get notified
+ * when the Configuration is reloaded from disk.
+ */
+public class ConfigurationManager {
+ public static final Log LOG = LogFactory.getLog(ConfigurationManager.class);
+
+ // The set of Configuration Observers. These classes would like to get
+ // notified when the configuration is reloaded from disk. This is a set
+ // constructed from a WeakHashMap, whose entries would be removed if the
+ // observer classes go out of scope.
+ private Set<ConfigurationObserver> configurationObservers =
+ Collections.newSetFromMap(new WeakHashMap<ConfigurationObserver,
+ Boolean>());
+
+ /**
+ * Register an observer class
+ * @param observer
+ */
+ public void registerObserver(ConfigurationObserver observer) {
+ synchronized (configurationObservers) {
+ configurationObservers.add(observer);
+ }
+ }
+
+ /**
+ * Deregister an observer class
+ * @param observer
+ */
+ public void deregisterObserver(ConfigurationObserver observer) {
+ synchronized (configurationObservers) {
+ configurationObservers.remove(observer);
+ }
+ }
+
+ /**
+ * The conf object has been repopulated from disk, and we have to notify
+ * all the observers that are expressed interest to do that.
+ */
+ public void notifyAllObservers(Configuration conf) {
+ synchronized (configurationObservers) {
+ for (ConfigurationObserver observer : configurationObservers) {
+ try {
+ observer.notifyOnChange(conf);
+ } catch (NullPointerException e) {
+ // Though not likely, but a null pointer exception might happen
+ // if the GC happens after this iteration started and before
+ // we call the notifyOnChange() method. A
+ // ConcurrentModificationException will not happen since GC doesn't
+ // change the structure of the map.
+ LOG.error("Encountered a NPE while notifying observers.");
+ } catch (Throwable t) {
+ LOG.error("Encountered a throwable while notifying observers: " +
+ t.getMessage());
+ }
+ }
+ }
+ }
+
+ /**
+ * Return the number of observers.
+ * @return
+ */
+ public int getNumObservers() {
+ return configurationObservers.size();
+ }
+}
Added: hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationObserver.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationObserver.java?rev=1484158&view=auto
==============================================================================
--- hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationObserver.java (added)
+++ hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/conf/ConfigurationObserver.java Sat May 18 18:18:32 2013
@@ -0,0 +1,36 @@
+/**
+ * Copyright 2013 The Apache Software Foundation
+ *
+ * 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.conf;
+
+import org.apache.hadoop.conf.Configuration;
+
+/**
+ * Every class that wants to observe changes in Configuration properties,
+ * must implement interface (and also, register itself with the
+ * <code>ConfigurationManager</code> object.
+ */
+public interface ConfigurationObserver {
+
+ /**
+ * This method would be called by the <code>ConfigurationManager</code>
+ * object when the <code>Configuration</code> object is reloaded from disk.
+ */
+ void notifyOnChange(Configuration conf);
+}
Modified: hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java?rev=1484158&r1=1484157&r2=1484158&view=diff
==============================================================================
--- hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java (original)
+++ hbase/branches/0.89-fb/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java Sat May 18 18:18:32 2013
@@ -108,6 +108,7 @@ import org.apache.hadoop.hbase.client.Ro
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.client.ServerConnection;
import org.apache.hadoop.hbase.client.ServerConnectionManager;
+import org.apache.hadoop.hbase.conf.ConfigurationManager;
import org.apache.hadoop.hbase.io.hfile.CacheConfig;
import org.apache.hadoop.hbase.io.hfile.LruBlockCache;
import org.apache.hadoop.hbase.io.hfile.LruBlockCache.CacheStats;
@@ -373,6 +374,10 @@ public class HRegionServer implements HR
public static boolean runMetrics = true;
+ // This object lets classes register themselves to get notified on
+ // Configuration changes.
+ public ConfigurationManager configurationManager;
+
public static long getResponseSizeLimit() {
return responseSizeLimit;
}
@@ -405,6 +410,7 @@ public class HRegionServer implements HR
this.abortRequested = false;
this.fsOk = true;
this.conf = conf;
+ this.configurationManager = new ConfigurationManager();
this.connection = ServerConnectionManager.getConnection(conf);
this.isOnline = false;
@@ -1453,6 +1459,14 @@ public class HRegionServer implements HR
return isOnline;
}
+ /**
+ * Return the ConfigurationManager object.
+ * @return
+ */
+ public ConfigurationManager getConfigurationManager() {
+ return this.configurationManager;
+ }
+
private void setupHLog(Path logDir, Path oldLogDir, int totalHLogCnt) throws IOException {
hlogs = new HLog[totalHLogCnt];
for (int i = 0; i < totalHLogCnt; i++) {
@@ -3788,9 +3802,13 @@ public class HRegionServer implements HR
public void updateConfiguration() {
LOG.info("Reloading the configuration from disk.");
conf.reloadConfiguration();
+ // TODO @gauravm
+ // Move this to the notifyOnChange() method in HRegionServer
for (HRegion r : onlineRegions.values()) {
r.updateConfiguration();
}
+ // Notify all the observers that the configuration has changed.
+ configurationManager.notifyAllObservers(conf);
}
public long getResponseQueueSize(){
Added: hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/conf/TestConfigurationManager.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/conf/TestConfigurationManager.java?rev=1484158&view=auto
==============================================================================
--- hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/conf/TestConfigurationManager.java (added)
+++ hbase/branches/0.89-fb/src/test/java/org/apache/hadoop/hbase/conf/TestConfigurationManager.java Sat May 18 18:18:32 2013
@@ -0,0 +1,133 @@
+/**
+ * Copyright 2013 The Apache Software Foundation
+ *
+ * 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.conf;
+
+import junit.framework.TestCase;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.assertTrue;
+
+public class TestConfigurationManager extends TestCase {
+ public static final Log LOG = LogFactory.getLog(TestConfigurationManager.class);
+
+ class DummyConfigurationObserver implements ConfigurationObserver {
+ private boolean notifiedOnChange = false;
+ private ConfigurationManager cm;
+
+ public DummyConfigurationObserver(ConfigurationManager cm) {
+ this.cm = cm;
+ register();
+ }
+
+ public void notifyOnChange(Configuration conf) {
+ notifiedOnChange = true;
+ }
+
+ // Was the observer notified on Configuration change?
+ public boolean wasNotifiedOnChange() {
+ return notifiedOnChange;
+ }
+
+ public void resetNotifiedOnChange() {
+ notifiedOnChange = false;
+ }
+
+ public void register() {
+ this.cm.registerObserver(this);
+ }
+
+ public void deregister() {
+ this.cm.deregisterObserver(this);
+ }
+ }
+
+ /**
+ * Test if observers get notified by the <code>ConfigurationManager</code>
+ * when the Configuration is reloaded.
+ */
+ public void testCheckIfObserversNotified() {
+ Configuration conf = new Configuration();
+ ConfigurationManager cm = new ConfigurationManager();
+ DummyConfigurationObserver d1 = new DummyConfigurationObserver(cm);
+
+ // Check if we get notified.
+ cm.notifyAllObservers(conf);
+ assertTrue(d1.wasNotifiedOnChange());
+ d1.resetNotifiedOnChange();
+
+ // Now check if we get notified on change with more than one observers.
+ DummyConfigurationObserver d2 = new DummyConfigurationObserver(cm);
+ cm.notifyAllObservers(conf);
+ assertTrue(d1.wasNotifiedOnChange());
+ d1.resetNotifiedOnChange();
+ assertTrue(d2.wasNotifiedOnChange());
+ d2.resetNotifiedOnChange();
+
+ // Now try deregistering an observer and verify that it was not notified
+ d2.deregister();
+ cm.notifyAllObservers(conf);
+ assertTrue(d1.wasNotifiedOnChange());
+ d1.resetNotifiedOnChange();
+ assertFalse(d2.wasNotifiedOnChange());
+ }
+
+ // Register an observer that will go out of scope immediately, allowing
+ // us to test that out of scope observers are deregistered.
+ private void registerLocalObserver(ConfigurationManager cm) {
+ new DummyConfigurationObserver(cm);
+ }
+
+ /**
+ * Test if out-of-scope observers are deregistered on GC.
+ */
+ public void testDeregisterOnOutOfScope() {
+ Configuration conf = new Configuration();
+ ConfigurationManager cm = new ConfigurationManager();
+
+ boolean outOfScopeObserversDeregistered = false;
+
+ // On my machine, I was able to cause a GC after around 5 iterations.
+ // If we do not cause a GC in 100k iterations, which is very unlikely,
+ // there might be something wrong with the GC.
+ for (int i = 0; i < 100000; i++) {
+ registerLocalObserver(cm);
+ cm.notifyAllObservers(conf);
+
+ // 'Suggest' the system to do a GC. We should be able to cause GC
+ // atleast once in the 2000 iterations.
+ System.gc();
+
+ // If GC indeed happened, all the observers (which are all out of scope),
+ // should have been deregistered.
+ if (cm.getNumObservers() <= i) {
+ outOfScopeObserversDeregistered = true;
+ break;
+ }
+ }
+ if (!outOfScopeObserversDeregistered) {
+ LOG.warn("Observers were not GC-ed! Something seems to be wrong.");
+ }
+ assertTrue(outOfScopeObserversDeregistered);
+ }
+}