Fix concurrency defects, remove unnecessary volatiles (#3701)

api/src/main/java/io/druid/guice/LifecycleScope.java

@@ -38,7 +38,7 @@ public class LifecycleScope implements Scope
   private final Lifecycle.Stage stage;
 
   private Lifecycle lifecycle;
-  private List<Object> instances = Lists.newLinkedList();
+  private final List<Object> instances = Lists.newLinkedList();
 
   public LifecycleScope(Lifecycle.Stage stage)
   {
@@ -47,8 +47,8 @@ public class LifecycleScope implements Scope
 
   public void setLifecycle(Lifecycle lifecycle)
   {
-    this.lifecycle = lifecycle;
     synchronized (instances) {
+      this.lifecycle = lifecycle;
       for (Object instance : instances) {
         lifecycle.addManagedInstance(instance);
       }

bytebuffer-collections/src/main/java/io/druid/collections/spatial/ImmutableNode.java

@@ -169,7 +169,7 @@ public class ImmutableNode
       {
         return new Iterator<ImmutableNode>()
         {
-          private volatile int count = 0;
+          private int count = 0;
 
           @Override
           public boolean hasNext()

bytebuffer-collections/src/main/java/io/druid/collections/spatial/RTree.java

@@ -39,7 +39,7 @@ public class RTree
   private final SplitStrategy splitStrategy;
   private final BitmapFactory bitmapFactory;
   private Node root;
-  private volatile int size;
+  private int size;
 
   public RTree(BitmapFactory bitmapFactory)
   {

common/src/main/java/io/druid/common/guava/CombiningSequence.java

@@ -20,7 +20,6 @@
 package io.druid.common.guava;
 
 import com.google.common.collect.Ordering;
-
 import io.druid.java.util.common.guava.Accumulator;
 import io.druid.java.util.common.guava.Sequence;
 import io.druid.java.util.common.guava.Yielder;
@@ -29,7 +28,6 @@ import io.druid.java.util.common.guava.YieldingAccumulator;
 import io.druid.java.util.common.guava.nary.BinaryFn;
 
 import java.io.IOException;
-import java.util.concurrent.atomic.AtomicReference;
 
 /**
  */
@@ -41,7 +39,7 @@ public class CombiningSequence<T> implements Sequence<T>
       BinaryFn<T, T, T> mergeFn
   )
   {
-    return new CombiningSequence<T>(baseSequence, ordering, mergeFn);
+    return new CombiningSequence<>(baseSequence, ordering, mergeFn);
   }
 
   private final Sequence<T> baseSequence;
@@ -62,16 +60,19 @@ public class CombiningSequence<T> implements Sequence<T>
   @Override
   public <OutType> OutType accumulate(OutType initValue, final Accumulator<OutType, T> accumulator)
   {
-    final AtomicReference<OutType> retVal = new AtomicReference<OutType>(initValue);
+    final CombiningAccumulator<OutType> combiningAccumulator = new CombiningAccumulator<>(initValue, accumulator);
-    final CombiningAccumulator<OutType> combiningAccumulator = new CombiningAccumulator<OutType>(retVal, accumulator);
     T lastValue = baseSequence.accumulate(null, combiningAccumulator);
-    return combiningAccumulator.accumulatedSomething() ? accumulator.accumulate(retVal.get(), lastValue) : initValue;
+    if (combiningAccumulator.accumulatedSomething()) {
+      return accumulator.accumulate(combiningAccumulator.retVal, lastValue);
+    } else {
+      return initValue;
+    }
   }
 
   @Override
   public <OutType> Yielder<OutType> toYielder(OutType initValue, final YieldingAccumulator<OutType, T> accumulator)
   {
-    final CombiningYieldingAccumulator<OutType, T> combiningAccumulator = new CombiningYieldingAccumulator<OutType, T>(
+    final CombiningYieldingAccumulator<OutType, T> combiningAccumulator = new CombiningYieldingAccumulator<>(
         ordering, mergeFn, accumulator
     );
 
@@ -81,7 +82,7 @@ public class CombiningSequence<T> implements Sequence<T>
     return makeYielder(baseYielder, combiningAccumulator, false);
   }
 
-  public <OutType> Yielder<OutType> makeYielder(
+  private <OutType> Yielder<OutType> makeYielder(
       final Yielder<T> yielder,
       final CombiningYieldingAccumulator<OutType, T> combiningAccumulator,
       boolean finalValue
@@ -152,11 +153,11 @@ public class CombiningSequence<T> implements Sequence<T>
     private final BinaryFn<T, T, T> mergeFn;
     private final YieldingAccumulator<OutType, T> accumulator;
 
-    private volatile OutType retVal;
+    private OutType retVal;
-    private volatile T lastMergedVal;
+    private T lastMergedVal;
-    private volatile boolean accumulatedSomething = false;
+    private boolean accumulatedSomething = false;
 
-    public CombiningYieldingAccumulator(
+    CombiningYieldingAccumulator(
         Ordering<T> ordering,
         BinaryFn<T, T, T> mergeFn,
         YieldingAccumulator<OutType, T> accumulator
@@ -219,12 +220,12 @@ public class CombiningSequence<T> implements Sequence<T>
       return t;
     }
 
-    public void accumulateLastValue()
+    void accumulateLastValue()
     {
       retVal = accumulator.accumulate(retVal, lastMergedVal);
     }
 
-    public boolean accumulatedSomething()
+    boolean accumulatedSomething()
     {
       return accumulatedSomething;
     }
@@ -232,18 +233,18 @@ public class CombiningSequence<T> implements Sequence<T>
 
   private class CombiningAccumulator<OutType> implements Accumulator<T, T>
   {
-    private final AtomicReference<OutType> retVal;
+    private OutType retVal;
     private final Accumulator<OutType, T> accumulator;
 
     private volatile boolean accumulatedSomething = false;
 
-    public CombiningAccumulator(AtomicReference<OutType> retVal, Accumulator<OutType, T> accumulator)
+    CombiningAccumulator(OutType retVal, Accumulator<OutType, T> accumulator)
     {
       this.retVal = retVal;
       this.accumulator = accumulator;
     }
 
-    public boolean accumulatedSomething()
+    boolean accumulatedSomething()
     {
       return accumulatedSomething;
     }
@@ -263,7 +264,7 @@ public class CombiningSequence<T> implements Sequence<T>
         return mergeFn.apply(prevValue, t);
       }
 
-      retVal.set(accumulator.accumulate(retVal.get(), prevValue));
+      retVal = accumulator.accumulate(retVal, prevValue);
       return t;
     }
   }

indexing-hadoop/src/main/java/io/druid/indexer/HadoopDruidIndexerConfig.java

@@ -213,8 +213,8 @@ public class HadoopDruidIndexerConfig
     return retVal;
   }
 
-  private volatile HadoopIngestionSpec schema;
+  private HadoopIngestionSpec schema;
-  private volatile PathSpec pathSpec;
+  private PathSpec pathSpec;
   private final Map<Long, ShardSpecLookup> shardSpecLookups = Maps.newHashMap();
   private final Map<Long, Map<ShardSpec, HadoopyShardSpec>> hadoopShardSpecLookup = Maps.newHashMap();
   private final QueryGranularity rollupGran;

indexing-service/src/main/java/io/druid/indexing/common/RetryPolicy.java

@@ -31,8 +31,8 @@ public class RetryPolicy
   private final long maxNumRetries;
   private final Duration maxRetryDelay;
 
-  private volatile Duration currRetryDelay;
+  private Duration currRetryDelay;
-  private volatile int retryCount;
+  private int retryCount;
 
   public RetryPolicy(RetryPolicyConfig config)
   {

indexing-service/src/main/java/io/druid/indexing/overlord/ForkingTaskRunner.java

@@ -67,6 +67,7 @@ import org.apache.commons.io.FileUtils;
 import org.joda.time.DateTime;
 import org.joda.time.Interval;
 
+import javax.annotation.concurrent.GuardedBy;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -548,7 +549,10 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogStreamer
         if (terminated) {
           log.info("Finished stopping in %,dms.", elapsed);
         } else {
-          final Set<String> stillRunning = ImmutableSet.copyOf(tasks.keySet());
+          final Set<String> stillRunning;
+          synchronized (tasks) {
+            stillRunning = ImmutableSet.copyOf(tasks.keySet());
+          }
 
           log.makeAlert("Failed to stop forked tasks")
              .addData("stillRunning", stillRunning)
@@ -670,6 +674,7 @@ public class ForkingTaskRunner implements TaskRunner, TaskLogStreamer
 
   // Save running tasks to a file, so they can potentially be restored on next startup. Suppresses exceptions that
   // occur while saving.
+  @GuardedBy("tasks")
   private void saveRunningTasks()
   {
     final File restoreFile = getRestoreFile();

java-util/src/main/java/io/druid/java/util/common/guava/LimitedYieldingAccumulator.java

@@ -1,70 +0,0 @@
-/*
- * Licensed to Metamarkets Group Inc. (Metamarkets) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. Metamarkets 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 io.druid.java.util.common.guava;
-
-/**
- *  @deprecated this class uses expensive volatile counter inside, but it is not thread-safe. It is going to be removed
- *  in the future.
- */
-
-@Deprecated
-public class LimitedYieldingAccumulator<OutType, T> extends YieldingAccumulator<OutType, T>
-{
-  private final int limit;
-  private final YieldingAccumulator<OutType, T> delegate;
-
-  private volatile int count = 0;
-
-  public LimitedYieldingAccumulator(
-      YieldingAccumulator<OutType, T> delegate, int limit
-  )
-  {
-    this.limit = limit;
-    this.delegate = delegate;
-  }
-
-  @Override
-  public void yield()
-  {
-    delegate.yield();
-  }
-
-  @Override
-  public boolean yielded()
-  {
-    return delegate.yielded();
-  }
-
-  @Override
-  public void reset()
-  {
-    delegate.reset();
-  }
-
-  @Override
-  public OutType accumulate(OutType accumulated, T in)
-  {
-    if (count < limit) {
-      count++;
-      return delegate.accumulate(accumulated, in);
-    }
-    return accumulated;
-  }
-}

processing/src/main/java/io/druid/query/aggregation/JavaScriptAggregator.java

@@ -40,7 +40,7 @@ public class JavaScriptAggregator implements Aggregator
   private final ObjectColumnSelector[] selectorList;
   private final ScriptAggregator script;
 
-  private volatile double current;
+  private double current;
 
   public JavaScriptAggregator(List<ObjectColumnSelector> selectorList, ScriptAggregator script)
   {

processing/src/main/java/io/druid/segment/QueryableIndexStorageAdapter.java

@@ -1328,7 +1328,7 @@ public class QueryableIndexStorageAdapter implements StorageAdapter
   {
     private final int rowCount;
     private final boolean descending;
-    private volatile int currentOffset;
+    private int currentOffset;
 
     NoFilterOffset(int currentOffset, int rowCount, boolean descending)
     {

processing/src/main/java/io/druid/segment/StringDimensionIndexer.java

@@ -147,12 +147,16 @@ public class StringDimensionIndexer implements DimensionIndexer<Integer, int[],
 
     public String getMinValue()
     {
-      return minValue;
+      synchronized (lock) {
+        return minValue;
+      }
     }
 
     public String getMaxValue()
     {
-      return maxValue;
+      synchronized (lock) {
+        return maxValue;
+      }
     }
 
     public SortedDimensionDictionary sort()

processing/src/main/java/io/druid/segment/incremental/IncrementalIndex.java

@@ -502,11 +502,6 @@ public abstract class IncrementalIndex<AggregatorType> implements Iterable<Row>,
     return TYPE_MAP.get(singleVal.getClass());
   }
 
-  public Map<String, DimensionDesc> getDimensionDescs()
-  {
-    return dimensionDescs;
-  }
-
   public Map<String, ColumnCapabilitiesImpl> getColumnCapabilities()
   {
     return columnCapabilities;

server/src/main/java/io/druid/segment/realtime/firehose/IngestSegmentFirehose.java

@@ -53,7 +53,7 @@ import java.util.Map;
 
 public class IngestSegmentFirehose implements Firehose
 {
-  private volatile Yielder<InputRow> rowYielder;
+  private Yielder<InputRow> rowYielder;
 
   public IngestSegmentFirehose(
       final List<WindowedStorageAdapter> adapters,

server/src/main/java/io/druid/segment/realtime/plumber/MessageTimeRejectionPolicyFactory.java

@@ -23,37 +23,66 @@ import io.druid.common.utils.JodaUtils;
 import org.joda.time.DateTime;
 import org.joda.time.Period;
 
+import java.util.concurrent.atomic.AtomicLongFieldUpdater;
+
 public class MessageTimeRejectionPolicyFactory implements RejectionPolicyFactory
 {
   @Override
   public RejectionPolicy create(final Period windowPeriod)
   {
     final long windowMillis = windowPeriod.toStandardDuration().getMillis();
+    return new MessageTimeRejectionPolicy(windowMillis, windowPeriod);
+  }
 
-    return new RejectionPolicy()
+  private static class MessageTimeRejectionPolicy implements RejectionPolicy
+  {
+    private static final AtomicLongFieldUpdater<MessageTimeRejectionPolicy> maxTimestampUpdater =
+        AtomicLongFieldUpdater.newUpdater(MessageTimeRejectionPolicy.class, "maxTimestamp");
+    private final long windowMillis;
+    private final Period windowPeriod;
+    private volatile long maxTimestamp;
+
+    public MessageTimeRejectionPolicy(long windowMillis, Period windowPeriod)
     {
-      private volatile long maxTimestamp = JodaUtils.MIN_INSTANT;
+      this.windowMillis = windowMillis;
+      this.windowPeriod = windowPeriod;
+      this.maxTimestamp = JodaUtils.MIN_INSTANT;
+    }
 
-      @Override
+    @Override
-      public DateTime getCurrMaxTime()
+    public DateTime getCurrMaxTime()
-      {
+    {
-        return new DateTime(maxTimestamp);
+      return new DateTime(maxTimestamp);
+    }
+
+    @Override
+    public boolean accept(long timestamp)
+    {
+      long maxTimestamp = this.maxTimestamp;
+      if (timestamp > maxTimestamp) {
+        maxTimestamp = tryUpdateMaxTimestamp(timestamp);
       }
 
-      @Override
+      return timestamp >= (maxTimestamp - windowMillis);
-      public boolean accept(long timestamp)
+    }
-      {
-        maxTimestamp = Math.max(maxTimestamp, timestamp);
 
-        return timestamp >= (maxTimestamp - windowMillis);
+    private long tryUpdateMaxTimestamp(long timestamp)
-      }
+    {
+      long currentMaxTimestamp;
+      do {
+        currentMaxTimestamp = maxTimestamp;
+        if (timestamp <= currentMaxTimestamp) {
+          return currentMaxTimestamp;
+        }
+      } while (!maxTimestampUpdater.compareAndSet(this, currentMaxTimestamp, timestamp));
+      return timestamp;
+    }
 
-      @Override
+    @Override
-      public String toString()
+    public String toString()
-      {
+    {
-        return String.format("messageTime-%s", windowPeriod);
+      return String.format("messageTime-%s", windowPeriod);
-      }
+    }
-    };
   }
 }
 

server/src/main/java/io/druid/server/coordinator/BalancerSegmentHolder.java

@@ -30,7 +30,7 @@ public class BalancerSegmentHolder
   private final DataSegment segment;
 
   // This is a pretty fugly hard coding of the maximum lifetime
-  private volatile int lifetime = 15;
+  private int lifetime = 15;
 
   public BalancerSegmentHolder(
       ImmutableDruidServer fromServer,

server/src/main/java/io/druid/server/log/FileRequestLogger.java

@@ -22,7 +22,6 @@ package io.druid.server.log;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.base.Charsets;
 import com.google.common.base.Throwables;
-
 import io.druid.java.util.common.concurrent.ScheduledExecutors;
 import io.druid.java.util.common.guava.CloseQuietly;
 import io.druid.java.util.common.lifecycle.LifecycleStart;
@@ -49,8 +48,8 @@ public class FileRequestLogger implements RequestLogger
 
   private final Object lock = new Object();
 
-  private volatile DateTime currentDay;
+  private DateTime currentDay;
-  private volatile OutputStreamWriter fileWriter;
+  private OutputStreamWriter fileWriter;
 
   public FileRequestLogger(ObjectMapper objectMapper, ScheduledExecutorService exec, File baseDir)
   {
@@ -67,12 +66,14 @@ public class FileRequestLogger implements RequestLogger
 
       MutableDateTime mutableDateTime = new DateTime().toMutableDateTime();
       mutableDateTime.setMillisOfDay(0);
-      currentDay = mutableDateTime.toDateTime();
+      synchronized (lock) {
+        currentDay = mutableDateTime.toDateTime();
 
-      fileWriter = new OutputStreamWriter(
+        fileWriter = new OutputStreamWriter(
-          new FileOutputStream(new File(baseDir, currentDay.toString("yyyy-MM-dd'.log'")), true),
+            new FileOutputStream(new File(baseDir, currentDay.toString("yyyy-MM-dd'.log'")), true),
-          Charsets.UTF_8
+            Charsets.UTF_8
-      );
+        );
+      }
       long nextDay = currentDay.plusDays(1).getMillis();
       Duration delay = new Duration(nextDay - new DateTime().getMillis());
 
@@ -85,10 +86,9 @@ public class FileRequestLogger implements RequestLogger
             @Override
             public ScheduledExecutors.Signal call()
             {
-              currentDay = currentDay.plusDays(1);
-
               try {
                 synchronized (lock) {
+                  currentDay = currentDay.plusDays(1);
                   CloseQuietly.close(fileWriter);
                   fileWriter = new OutputStreamWriter(
                       new FileOutputStream(new File(baseDir, currentDay.toString()), true),