fix crash with filtered aggregator at ingestion time

- only for selector filter because extraction filter is not supported as
  cardinality is not fixed at ingestion time

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

@@ -151,8 +151,6 @@ public class OffheapIncrementalIndex extends IncrementalIndex<BufferAggregator>
     selectors = Maps.newHashMap();
     aggOffsetInBuffer = new int[metrics.length];
 
-    BufferAggregator[] aggregators = new BufferAggregator[metrics.length];
-
     for (int i = 0; i < metrics.length; i++) {
       AggregatorFactory agg = metrics[i];
 
@@ -167,7 +165,6 @@ public class OffheapIncrementalIndex extends IncrementalIndex<BufferAggregator>
           new OnheapIncrementalIndex.ObjectCachingColumnSelectorFactory(columnSelectorFactory)
       );
 
-      aggregators[i] = agg.factorizeBuffered(columnSelectorFactory);
       if (i == 0) {
         aggOffsetInBuffer[i] = 0;
       } else {
@@ -177,7 +174,7 @@ public class OffheapIncrementalIndex extends IncrementalIndex<BufferAggregator>
 
     aggsTotalSize = aggOffsetInBuffer[metrics.length - 1] + metrics[metrics.length - 1].getMaxIntermediateSize();
 
-    return aggregators;
+    return new BufferAggregator[metrics.length];
   }
 
   @Override
@@ -203,6 +200,15 @@ public class OffheapIncrementalIndex extends IncrementalIndex<BufferAggregator>
         bufferOffset = indexAndOffset[1];
         aggBuffer = aggBuffers.get(bufferIndex).get();
       } else {
+        rowContainer.set(row);
+        for (int i = 0; i < metrics.length; i++) {
+          final AggregatorFactory agg = metrics[i];
+          getAggs()[i] = agg.factorizeBuffered(
+              makeColumnSelectorFactory(agg, rowSupplier, deserializeComplexMetrics)
+          );
+        }
+        rowContainer.set(null);
+
         bufferIndex = aggBuffers.size() - 1;
         ByteBuffer lastBuffer = aggBuffers.isEmpty() ? null : aggBuffers.get(aggBuffers.size() - 1).get();
         int[] lastAggregatorsIndexAndOffset = indexAndOffsets.isEmpty()

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

@@ -155,12 +155,15 @@ public class OnheapIncrementalIndex extends IncrementalIndex<Aggregator>
     } else {
       aggs = new Aggregator[metrics.length];
 
+      rowContainer.set(row);
       for (int i = 0; i < metrics.length; i++) {
         final AggregatorFactory agg = metrics[i];
         aggs[i] = agg.factorize(
             selectors.get(agg.getName())
         );
       }
+      rowContainer.set(null);
+
       final Integer rowIndex = indexIncrement.getAndIncrement();
 
       concurrentSet(rowIndex, aggs);

processing/src/test/java/io/druid/segment/incremental/IncrementalIndexTest.java

@@ -29,6 +29,8 @@ import io.druid.granularity.QueryGranularity;
 import io.druid.query.aggregation.AggregatorFactory;
 import io.druid.query.aggregation.CountAggregatorFactory;
 import io.druid.segment.CloserRule;
+import io.druid.query.aggregation.FilteredAggregatorFactory;
+import io.druid.query.filter.SelectorDimFilter;
 import org.joda.time.DateTime;
 import org.junit.Rule;
 import org.junit.Test;
@@ -73,7 +75,15 @@ public class IncrementalIndexTest
                   public IncrementalIndex createIndex()
                   {
                     return new OnheapIncrementalIndex(
-                        0, QueryGranularity.MINUTE, new AggregatorFactory[]{new CountAggregatorFactory("cnt")}, 1000
+                        0,
+                        QueryGranularity.MINUTE,
+                        new AggregatorFactory[]{
+                            new FilteredAggregatorFactory(
+                                new CountAggregatorFactory("cnt"),
+                                new SelectorDimFilter("billy", "A")
+                            )
+                        },
+                        1000
                     );
                   }
                 }
@@ -88,7 +98,12 @@ public class IncrementalIndexTest
                     return new OffheapIncrementalIndex(
                         0L,
                         QueryGranularity.NONE,
-                        new AggregatorFactory[]{new CountAggregatorFactory("cnt")},
+                        new AggregatorFactory[]{
+                            new FilteredAggregatorFactory(
+                                new CountAggregatorFactory("cnt"),
+                                new SelectorDimFilter("billy", "A")
+                            )
+                        },
                         1000000,
                         new StupidPool<ByteBuffer>(
                             new Supplier<ByteBuffer>()
@@ -104,7 +119,6 @@ public class IncrementalIndexTest
                   }
                 }
             }
-
         }
     );
   }
@@ -153,6 +167,13 @@ public class IncrementalIndexTest
             ImmutableMap.<String, Object>of("billy", "A", "joe", "B")
         )
     );
+    index.add(
+        new MapBasedInputRow(
+            new DateTime().minus(1).getMillis(),
+            Lists.newArrayList("billy", "joe"),
+            ImmutableMap.<String, Object>of("billy", "C", "joe", "B")
+        )
+    );
     index.add(
         new MapBasedInputRow(
             new DateTime().minus(1).getMillis(),