HBASE-24402 Moving the meta region causes MetricsException when using above 2.6.0 hadoop version

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/hbase/metrics/impl/GlobalMetricRegistriesAdapter.java

@@ -18,17 +18,13 @@
 package org.apache.hadoop.hbase.metrics.impl;
 
 
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
-import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-import org.apache.commons.lang.reflect.FieldUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.metrics.MetricRegistries;
@@ -37,11 +33,8 @@
 import org.apache.hadoop.metrics2.MetricsCollector;
 import org.apache.hadoop.metrics2.MetricsExecutor;
 import org.apache.hadoop.metrics2.MetricsSource;
-import org.apache.hadoop.metrics2.MetricsSystem;
 import org.apache.hadoop.metrics2.impl.JmxCacheBuster;
-import org.apache.hadoop.metrics2.impl.MetricsSystemImpl;
 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
-import org.apache.hadoop.metrics2.lib.DefaultMetricsSystemHelper;
 import org.apache.hadoop.metrics2.lib.MetricsExecutorImpl;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -87,7 +80,6 @@ public void getMetrics(MetricsCollector collector, boolean all) {
 
   private final MetricsExecutor executor;
   private final AtomicBoolean stopped;
-  private final DefaultMetricsSystemHelper helper;
   private final HBaseMetrics2HadoopMetricsAdapter metricsAdapter;
   private final HashMap<MetricRegistryInfo, MetricsSourceAdapter> registeredSources;
 
@@ -96,7 +88,6 @@ private GlobalMetricRegistriesAdapter() {
     this.stopped = new AtomicBoolean(false);
     this.metricsAdapter = new HBaseMetrics2HadoopMetricsAdapter();
     this.registeredSources = new HashMap<>();
-    this.helper = new DefaultMetricsSystemHelper();
     executor.getExecutor().scheduleAtFixedRate(new Runnable(){
       @Override
       public void run() {
@@ -167,67 +158,13 @@ private void doRun() {
         if (LOG.isDebugEnabled()) {
           LOG.debug("Removing adapter for the MetricRegistry: " + info.getMetricsJmxContext());
         }
-        synchronized(DefaultMetricsSystem.instance()) {
-          unregisterSource(info);
-          helper.removeSourceName(info.getMetricsJmxContext());
-          helper.removeObjectName(info.getMetricsJmxContext());
-          it.remove();
-          removed = true;
-        }
+        DefaultMetricsSystem.instance().unregisterSource(info.getMetricsJmxContext());
+        it.remove();
+        removed = true;
       }
     }
     if (removed) {
       JmxCacheBuster.clearJmxCache();
     }
   }
-
-  /**
-   * Use reflection to unregister the Hadoop metric source, since MetricsSystem#unregisterSource()
-   * is only available in Hadoop 2.6+ (HADOOP-10839)
-   */
-  @VisibleForTesting
-  protected void unregisterSource(MetricRegistryInfo info) {
-    // unregisterSource is only available in Hadoop 2.6+ (HADOOP-10839). Don't unregister for now
-    MetricsSystem metricsSystem = DefaultMetricsSystem.instance();
-    if (metricsSystem instanceof MetricsSystemImpl) {
-      try {
-        // it's actually a Map<String, MetricsSourceAdapter> , but MetricsSourceAdapter isn't
-        // accessible
-        @SuppressWarnings("unchecked")
-        Map<String, Object> sources =
-            (Map<String, Object>) FieldUtils.readField(metricsSystem, "sources", true);
-        String sourceName = info.getMetricsJmxContext();
-        if (sources.containsKey(sourceName)) {
-          Object sourceAdapter = sources.get(sourceName);
-          Method method = null;
-          try {
-            method = sourceAdapter.getClass().getDeclaredMethod("stop");
-          } catch (NoSuchMethodException e) {
-            LOG.info("Stop method not found on MetricsSourceAdapter");
-          } catch (SecurityException e) {
-            LOG.info("Don't have access to call stop method not found on MetricsSourceAdapter", e);
-          }
-          if (method != null) {
-            method.setAccessible(true);
-            try {
-              method.invoke(sourceAdapter);
-            } catch (IllegalArgumentException | InvocationTargetException e) {
-              LOG.warn("Couldn't invoke stop on metrics source adapter: " + sourceName);
-              e.printStackTrace();
-            }
-          }
-          sources.remove(sourceName);
-
-        }
-        @SuppressWarnings("unchecked")
-        Map<String, MetricsSource> allSources =
-            (Map<String, MetricsSource>) FieldUtils.readField(metricsSystem, "allSources", true);
-        if (allSources.containsKey(sourceName)) {
-          allSources.remove(sourceName);
-        }
-      } catch (IllegalAccessException e) {
-        LOG.warn("Error unregistering metric source " + info.getMetricsJmxContext());
-      }
-    }
-  }
 }

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/metrics2/lib/DefaultMetricsSystemHelper.java

@@ -17,9 +17,7 @@
  */
 package org.apache.hadoop.metrics2.lib;
 
-import java.lang.reflect.Field;
 import java.lang.reflect.Method;
-import java.util.HashMap;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -28,8 +26,6 @@ public class DefaultMetricsSystemHelper {
 
   private static final Log LOG = LogFactory.getLog(DefaultMetricsSystemHelper.class);
   private final Method removeObjectMethod;
-  private final Field sourceNamesField;
-  private final Field mapField;
 
   public DefaultMetricsSystemHelper() {
     Class<? extends DefaultMetricsSystem> clazz = DefaultMetricsSystem.INSTANCE.getClass();
@@ -41,20 +37,6 @@ public DefaultMetricsSystemHelper() {
       m = null;
     }
     removeObjectMethod = m;
-
-    Field f1, f2;
-    try {
-      f1 = clazz.getDeclaredField("sourceNames");
-      f1.setAccessible(true);
-      f2 = UniqueNames.class.getDeclaredField("map");
-      f2.setAccessible(true);
-    } catch (NoSuchFieldException e) {
-      LOG.trace(e);
-      f1 = null;
-      f2 = null;
-    }
-    sourceNamesField = f1;
-    mapField = f2;
   }
 
   public boolean removeObjectName(final String name) {
@@ -70,30 +52,4 @@ public boolean removeObjectName(final String name) {
     }
     return false;
   }
-
-  /**
-   * Unfortunately Hadoop tries to be too-clever and permanently keeps track of all names registered
-   * so far as a Source, thus preventing further re-registration of the source with the same name.
-   * In case of dynamic metrics tied to region-lifecycles, this becomes a problem because we would
-   * like to be able to re-register and remove with the same name. Otherwise, it is resource leak.
-   * This ugly code manually removes the name from the UniqueNames map.
-   * TODO: May not be needed for Hadoop versions after YARN-5190.
-   */
-  public void removeSourceName(String name) {
-    if (sourceNamesField == null || mapField == null) {
-      return;
-    }
-    try {
-      Object sourceNames = sourceNamesField.get(DefaultMetricsSystem.INSTANCE);
-      HashMap map = (HashMap) mapField.get(sourceNames);
-      synchronized (sourceNames) {
-        map.remove(name);
-      }
-    } catch (Exception ex) {
-      if (LOG.isTraceEnabled()) {
-        LOG.trace("Received exception while trying to access Hadoop Metrics classes via reflection.",
-            ex);
-      }
-    }
-  }
 }