diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryBTreeOperationsHelper.java b/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryBTreeOperationsHelper.java
index c5c214e..47b2567 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryBTreeOperationsHelper.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryBTreeOperationsHelper.java
@@ -138,7 +138,8 @@
                         dataset.getDatasetId()), mergePolicyFactory, mergePolicyFactoryProperties,
                         new SecondaryIndexOperationTrackerProvider(dataset.getDatasetId()),
                         AsterixRuntimeComponentsProvider.RUNTIME_PROVIDER, LSMBTreeIOOperationCallbackFactory.INSTANCE,
-                        storageProperties.getBloomFilterFalsePositiveRate(), false), NoOpOperationCallbackFactory.INSTANCE);
+                        storageProperties.getBloomFilterFalsePositiveRate(), false),
+                NoOpOperationCallbackFactory.INSTANCE);
         AlgebricksPartitionConstraintHelper.setPartitionConstraintInJobSpec(spec, compactOp,
                 secondaryPartitionConstraint);
         spec.addRoot(compactOp);
diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryRTreeOperationsHelper.java b/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryRTreeOperationsHelper.java
index 5a0db1d..225ee53 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryRTreeOperationsHelper.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/file/SecondaryRTreeOperationsHelper.java
@@ -49,6 +49,7 @@
 import edu.uci.ics.hyracks.api.job.JobSpecification;
 import edu.uci.ics.hyracks.dataflow.std.base.AbstractOperatorDescriptor;
 import edu.uci.ics.hyracks.dataflow.std.connectors.OneToOneConnectorDescriptor;
+import edu.uci.ics.hyracks.dataflow.std.sort.ExternalSortOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.btree.dataflow.BTreeSearchOperatorDescriptor;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
 import edu.uci.ics.hyracks.storage.am.common.api.IPrimitiveValueProviderFactory;
@@ -174,6 +175,11 @@
             selectOp = createFilterNullsSelectOp(spec, numNestedSecondaryKeyFields);
         }
 
+        // Sort by secondary keys.
+        ExternalSortOperatorDescriptor sortOp = createSortOp(spec,
+                new IBinaryComparatorFactory[] { AqlMetadataProvider.proposeLinearizer(keyType,
+                        secondaryComparatorFactories.length) }, secondaryRecDesc);
+
         AsterixStorageProperties storageProperties = propertiesProvider.getStorageProperties();
         // Create secondary RTree bulk load op.
         TreeIndexBulkLoadOperatorDescriptor secondaryBulkLoadOp = createTreeIndexBulkLoadOp(spec,
@@ -190,10 +196,11 @@
         spec.connect(new OneToOneConnectorDescriptor(spec), primaryScanOp, 0, asterixAssignOp, 0);
         if (anySecondaryKeyIsNullable) {
             spec.connect(new OneToOneConnectorDescriptor(spec), asterixAssignOp, 0, selectOp, 0);
-            spec.connect(new OneToOneConnectorDescriptor(spec), selectOp, 0, secondaryBulkLoadOp, 0);
+            spec.connect(new OneToOneConnectorDescriptor(spec), selectOp, 0, sortOp, 0);
         } else {
-            spec.connect(new OneToOneConnectorDescriptor(spec), asterixAssignOp, 0, secondaryBulkLoadOp, 0);
+            spec.connect(new OneToOneConnectorDescriptor(spec), asterixAssignOp, 0, sortOp, 0);
         }
+        spec.connect(new OneToOneConnectorDescriptor(spec), sortOp, 0, secondaryBulkLoadOp, 0);
         spec.addRoot(secondaryBulkLoadOp);
         spec.setConnectorPolicyAssignmentPolicy(new ConnectorPolicyAssignmentPolicy());
         return spec;