diff --git a/server/src/main/java/io/druid/segment/realtime/plumber/RealtimePlumber.java b/server/src/main/java/io/druid/segment/realtime/plumber/RealtimePlumber.java
index b9d49396682..a4a00a4fdb8 100644
--- a/server/src/main/java/io/druid/segment/realtime/plumber/RealtimePlumber.java
+++ b/server/src/main/java/io/druid/segment/realtime/plumber/RealtimePlumber.java
@@ -48,8 +48,8 @@ import io.druid.common.guava.ThreadRenamingCallable;
 import io.druid.common.guava.ThreadRenamingRunnable;
 import io.druid.common.utils.VMUtils;
 import io.druid.concurrent.Execs;
-import io.druid.data.input.Committer;
 import io.druid.concurrent.TaskThreadPriority;
+import io.druid.data.input.Committer;
 import io.druid.data.input.InputRow;
 import io.druid.query.MetricsEmittingQueryRunner;
 import io.druid.query.NoopQueryRunner;
@@ -59,7 +59,6 @@ import io.druid.query.QueryRunnerFactory;
 import io.druid.query.QueryRunnerFactoryConglomerate;
 import io.druid.query.QueryRunnerHelper;
 import io.druid.query.QueryToolChest;
-import io.druid.query.ReportTimelineMissingSegmentQueryRunner;
 import io.druid.query.SegmentDescriptor;
 import io.druid.query.spec.SpecificSegmentQueryRunner;
 import io.druid.query.spec.SpecificSegmentSpec;
@@ -69,7 +68,6 @@ import io.druid.segment.IndexSpec;
 import io.druid.segment.Metadata;
 import io.druid.segment.QueryableIndex;
 import io.druid.segment.QueryableIndexSegment;
-import io.druid.segment.ReferenceCountingSegment;
 import io.druid.segment.Segment;
 import io.druid.segment.incremental.IndexSizeExceededException;
 import io.druid.segment.indexing.DataSchema;
@@ -90,7 +88,6 @@ import org.joda.time.Interval;
 import org.joda.time.Period;
 
 import javax.annotation.Nullable;
-import javax.ws.rs.HEAD;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FilenameFilter;
@@ -481,50 +478,52 @@ public class RealtimePlumber implements Plumber
     mergeExecutor.execute(
         new ThreadRenamingRunnable(threadName)
         {
+          final Interval interval = sink.getInterval();
+          Stopwatch mergeStopwatch = null;
+
           @Override
           public void doRun()
           {
-            final Interval interval = sink.getInterval();
-
-            // Bail out if this sink has been abandoned by a previously-executed task.
-            if (sinks.get(truncatedTime) != sink) {
-              log.info("Sink[%s] was abandoned, bailing out of persist-n-merge.", sink);
-              return;
-            }
-
-            // Use a file to indicate that pushing has completed.
-            final File persistDir = computePersistDir(schema, interval);
-            final File mergedTarget = new File(persistDir, "merged");
-            final File isPushedMarker = new File(persistDir, "isPushedMarker");
-
-            if (!isPushedMarker.exists()) {
-              removeSegment(sink, mergedTarget);
-              if (mergedTarget.exists()) {
-                log.wtf("Merged target[%s] exists?!", mergedTarget);
+            try {
+              // Bail out if this sink has been abandoned by a previously-executed task.
+              if (sinks.get(truncatedTime) != sink) {
+                log.info("Sink[%s] was abandoned, bailing out of persist-n-merge.", sink);
+                return;
+              }
+
+              // Use a file to indicate that pushing has completed.
+              final File persistDir = computePersistDir(schema, interval);
+              final File mergedTarget = new File(persistDir, "merged");
+              final File isPushedMarker = new File(persistDir, "isPushedMarker");
+
+              if (!isPushedMarker.exists()) {
+                removeSegment(sink, mergedTarget);
+                if (mergedTarget.exists()) {
+                  log.wtf("Merged target[%s] exists?!", mergedTarget);
+                  return;
+                }
+              } else {
+                log.info("Already pushed sink[%s]", sink);
                 return;
               }
-            } else {
-              log.info("Already pushed sink[%s]", sink);
-              return;
-            }
 
             /*
             Note: it the plumber crashes after persisting a subset of hydrants then might duplicate data as these
             hydrants will be read but older commitMetadata will be used. fixing this possibly needs structural
             changes to plumber.
              */
-            for (FireHydrant hydrant : sink) {
-              synchronized (hydrant) {
-                if (!hydrant.hasSwapped()) {
-                  log.info("Hydrant[%s] hasn't swapped yet, swapping. Sink[%s]", hydrant, sink);
-                  final int rowCount = persistHydrant(hydrant, schema, interval, null);
-                  metrics.incrementRowOutputCount(rowCount);
+              for (FireHydrant hydrant : sink) {
+                synchronized (hydrant) {
+                  if (!hydrant.hasSwapped()) {
+                    log.info("Hydrant[%s] hasn't swapped yet, swapping. Sink[%s]", hydrant, sink);
+                    final int rowCount = persistHydrant(hydrant, schema, interval, null);
+                    metrics.incrementRowOutputCount(rowCount);
+                  }
                 }
               }
-            }
-            final long mergeThreadCpuTime = VMUtils.safeGetThreadCpuTime();
-            final Stopwatch mergeStopwatch = Stopwatch.createStarted();
-            try {
+              final long mergeThreadCpuTime = VMUtils.safeGetThreadCpuTime();
+              mergeStopwatch = Stopwatch.createStarted();
+
               List<QueryableIndex> indexes = Lists.newArrayList();
               for (FireHydrant fireHydrant : sink) {
                 Segment segment = fireHydrant.getSegment();
@@ -575,7 +574,9 @@ public class RealtimePlumber implements Plumber
               }
             }
             finally {
-              mergeStopwatch.stop();
+              if (mergeStopwatch != null) {
+                mergeStopwatch.stop();
+              }
             }
           }
         }