diff --git a/merger/src/main/java/com/metamx/druid/merger/common/index/EventReceiverFirehoseFactory.java b/merger/src/main/java/com/metamx/druid/merger/common/index/EventReceiverFirehoseFactory.java
index bc7c65e9897..d2376e5d0c2 100644
--- a/merger/src/main/java/com/metamx/druid/merger/common/index/EventReceiverFirehoseFactory.java
+++ b/merger/src/main/java/com/metamx/druid/merger/common/index/EventReceiverFirehoseFactory.java
@@ -7,6 +7,7 @@ import com.fasterxml.jackson.annotation.JsonTypeName;
 import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
+import com.google.common.collect.Lists;
 import com.metamx.druid.indexer.data.MapInputRowParser;
 import com.metamx.druid.input.InputRow;
 import com.metamx.druid.realtime.firehose.Firehose;
@@ -15,6 +16,7 @@ import com.metamx.emitter.EmittingLogger;
 
 import java.io.IOException;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.concurrent.ArrayBlockingQueue;
@@ -84,14 +86,14 @@ public class EventReceiverFirehoseFactory implements FirehoseFactory
 
   public class EventReceiverFirehose implements EventReceiver, Firehose
   {
-    private final BlockingQueue<Map<String, Object>> buffer;
+    private final BlockingQueue<InputRow> buffer;
     private final Object readLock = new Object();
-    private volatile Map<String, Object> nextEvent = null;
+    private volatile InputRow nextRow = null;
     private volatile boolean closed = false;
 
     public EventReceiverFirehose()
     {
-      this.buffer = new ArrayBlockingQueue<Map<String, Object>>(bufferSize);
+      this.buffer = new ArrayBlockingQueue<InputRow>(bufferSize);
     }
 
     @Override
@@ -99,11 +101,17 @@ public class EventReceiverFirehoseFactory implements FirehoseFactory
     {
       log.debug("Adding %,d events to firehose: %s", events.size(), firehoseId);
 
+      final List<InputRow> rows = Lists.newArrayList();
+      for (final Map<String, Object> event : events) {
+        // Might throw an exception. We'd like that to happen now, instead of while adding to the row buffer.
+        rows.add(parser.parse(event));
+      }
+
       try {
-        for (final Map<String, Object> event : events) {
+        for (final InputRow row : rows) {
           boolean added = false;
           while (!closed && !added) {
-            added = buffer.offer(event, 500, TimeUnit.MILLISECONDS);
+            added = buffer.offer(row, 500, TimeUnit.MILLISECONDS);
           }
 
           if (!added) {
@@ -121,8 +129,8 @@ public class EventReceiverFirehoseFactory implements FirehoseFactory
     {
       synchronized (readLock) {
         try {
-          while (!closed && nextEvent == null) {
-            nextEvent = buffer.poll(500, TimeUnit.MILLISECONDS);
+          while (!closed && nextRow == null) {
+            nextRow = buffer.poll(500, TimeUnit.MILLISECONDS);
           }
         }
         catch (InterruptedException e) {
@@ -130,7 +138,7 @@ public class EventReceiverFirehoseFactory implements FirehoseFactory
           throw Throwables.propagate(e);
         }
 
-        return nextEvent != null;
+        return nextRow != null;
       }
     }
 
@@ -138,14 +146,13 @@ public class EventReceiverFirehoseFactory implements FirehoseFactory
     public InputRow nextRow()
     {
       synchronized (readLock) {
-        final Map<String, Object> event = nextEvent;
+        final InputRow row = nextRow;
 
-        if (event == null) {
+        if (row == null) {
           throw new NoSuchElementException();
         } else {
-          // If nextEvent is unparseable, don't return it again
-          nextEvent = null;
-          return parser.parse(event);
+          nextRow = null;
+          return row;
         }
       }
     }