fix race while index closing and querying

indexing-service/src/main/java/io/druid/indexing/common/index/YeOldePlumberSchool.java

@@ -223,7 +223,6 @@ public class YeOldePlumberSchool implements PlumberSchool
             );
 
             indexToPersist.swapSegment(null);
-            index.close();
             metrics.incrementRowOutputCount(rowsToPersist);
 
             spilled.add(dirToPersist);

processing/src/main/java/io/druid/query/GroupByParallelQueryRunner.java

@@ -63,7 +63,6 @@ public class GroupByParallelQueryRunner implements QueryRunner<Row>
   private final QueryWatcher queryWatcher;
   private final StupidPool<ByteBuffer> bufferPool;
 
-
   public GroupByParallelQueryRunner(
       ExecutorService exec,
       Ordering<Row> ordering,
@@ -155,17 +154,21 @@ public class GroupByParallelQueryRunner implements QueryRunner<Row>
     catch (InterruptedException e) {
       log.warn(e, "Query interrupted, cancelling pending results, query id [%s]", query.getId());
       futures.cancel(true);
+      indexAccumulatorPair.lhs.close();
       throw new QueryInterruptedException("Query interrupted");
     }
     catch (CancellationException e) {
+      indexAccumulatorPair.lhs.close();
       throw new QueryInterruptedException("Query cancelled");
     }
     catch (TimeoutException e) {
+      indexAccumulatorPair.lhs.close();
       log.info("Query timeout, cancelling pending results for query id [%s]", query.getId());
       futures.cancel(true);
       throw new QueryInterruptedException("Query timeout");
     }
     catch (ExecutionException e) {
+      indexAccumulatorPair.lhs.close();
       throw Throwables.propagate(e.getCause());
     }
 
@@ -173,7 +176,8 @@ public class GroupByParallelQueryRunner implements QueryRunner<Row>
         Sequences.simple(
             indexAccumulatorPair.lhs
                                 .iterableWithPostAggregations(null)
-        ), indexAccumulatorPair.lhs
+        ),
+        indexAccumulatorPair.lhs
     );
   }
 

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

@@ -68,6 +68,6 @@ public class IncrementalIndexSegment implements Segment
   @Override
   public void close() throws IOException
   {
-    // do nothing
+    index.close();
   }
 }

server/src/main/java/io/druid/segment/realtime/FireHydrant.java

@@ -19,17 +19,21 @@
 
 package io.druid.segment.realtime;
 
+import com.google.api.client.repackaged.com.google.common.base.Throwables;
 import io.druid.segment.IncrementalIndexSegment;
+import io.druid.segment.ReferenceCountingSegment;
 import io.druid.segment.Segment;
 import io.druid.segment.incremental.IncrementalIndex;
 
+import java.io.IOException;
+
 /**
-*/
+ */
 public class FireHydrant
 {
-  private volatile IncrementalIndex index;
-  private volatile Segment adapter;
   private final int count;
+  private volatile IncrementalIndex index;
+  private volatile ReferenceCountingSegment adapter;
 
   public FireHydrant(
       IncrementalIndex index,
@@ -38,7 +42,7 @@ public class FireHydrant
   )
   {
     this.index = index;
-    this.adapter = new IncrementalIndexSegment(index, segmentIdentifier);
+    this.adapter = new ReferenceCountingSegment(new IncrementalIndexSegment(index, segmentIdentifier));
     this.count = count;
   }
 
@@ -48,7 +52,7 @@ public class FireHydrant
   )
   {
     this.index = null;
-    this.adapter = adapter;
+    this.adapter = new ReferenceCountingSegment(adapter);
     this.count = count;
   }
 
@@ -57,7 +61,7 @@ public class FireHydrant
     return index;
   }
 
-  public Segment getSegment()
+  public ReferenceCountingSegment getSegment()
   {
     return adapter;
   }
@@ -74,7 +78,15 @@ public class FireHydrant
 
   public void swapSegment(Segment adapter)
   {
-    this.adapter = adapter;
+    if (this.adapter != null) {
+      try {
+        this.adapter.close();
+      }
+      catch (IOException e) {
+        throw Throwables.propagate(e);
+      }
+    }
+    this.adapter = new ReferenceCountingSegment(adapter);
     this.index = null;
   }
 

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

@@ -19,12 +19,10 @@ import com.metamx.emitter.service.ServiceEmitter;
 import com.metamx.emitter.service.ServiceMetricEvent;
 import io.druid.client.FilteredServerView;
 import io.druid.client.ServerView;
-import io.druid.collections.StupidPool;
 import io.druid.common.guava.ThreadRenamingCallable;
 import io.druid.common.guava.ThreadRenamingRunnable;
 import io.druid.concurrent.Execs;
 import io.druid.data.input.InputRow;
-import io.druid.guice.annotations.Global;
 import io.druid.query.MetricsEmittingQueryRunner;
 import io.druid.query.Query;
 import io.druid.query.QueryRunner;
@@ -59,10 +57,10 @@ import org.joda.time.Interval;
 import org.joda.time.Period;
 
 import javax.annotation.Nullable;
+import java.io.Closeable;
 import java.io.File;
 import java.io.FilenameFilter;
 import java.io.IOException;
-import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
@@ -76,10 +74,8 @@ import java.util.concurrent.ScheduledExecutorService;
 public class RealtimePlumber implements Plumber
 {
   private static final EmittingLogger log = new EmittingLogger(RealtimePlumber.class);
-
   private final DataSchema schema;
   private final RealtimeTuningConfig config;
-
   private final RejectionPolicy rejectionPolicy;
   private final FireDepartmentMetrics metrics;
   private final ServiceEmitter emitter;
@@ -253,8 +249,20 @@ public class RealtimePlumber implements Plumber
                                           @Override
                                           public QueryRunner<T> apply(FireHydrant input)
                                           {
+                                            // Prevent the underlying segment from closing when its being iterated
+                                            final Closeable closeable = input.getSegment().increment();
+                                            try {
                                               return factory.createRunner(input.getSegment());
                                             }
+                                            finally {
+                                              try {
+                                                closeable.close();
+                                              }
+                                              catch (IOException e) {
+                                                throw Throwables.propagate(e);
+                                              }
+                                            }
+                                          }
                                         }
                                     )
                                 )
@@ -717,8 +725,6 @@ public class RealtimePlumber implements Plumber
                 IndexIO.loadIndex(persistedFile)
             )
         );
-        //TODO: can there be some races here ?
-        index.close();
         return numRows;
       }
       catch (IOException e) {