diff --git a/sql/catalyst/src/main/java/org/apache/spark/sql/execution/UnsafeExternalRowSorter.java b/sql/catalyst/src/main/java/org/apache/spark/sql/execution/UnsafeExternalRowSorter.java
index c29b002a998ca..295e2889dffce 100644
--- a/sql/catalyst/src/main/java/org/apache/spark/sql/execution/UnsafeExternalRowSorter.java
+++ b/sql/catalyst/src/main/java/org/apache/spark/sql/execution/UnsafeExternalRowSorter.java
@@ -211,7 +211,10 @@ public int compare(Object baseObj1, long baseOff1, Object baseObj2, long baseOff
       // TODO: Why are the sizes -1?
       row1.pointTo(baseObj1, baseOff1, -1);
       row2.pointTo(baseObj2, baseOff2, -1);
-      return ordering.compare(row1, row2);
+      int comparison = ordering.compare(row1, row2);
+      row1.pointTo(null, 0L, -1);
+      row2.pointTo(null, 0L, -1);
+      return comparison;
     }
   }
 }
diff --git a/sql/core/src/main/java/org/apache/spark/sql/execution/UnsafeKVExternalSorter.java b/sql/core/src/main/java/org/apache/spark/sql/execution/UnsafeKVExternalSorter.java
index ee5bcfd02c79e..37a779c028ef4 100644
--- a/sql/core/src/main/java/org/apache/spark/sql/execution/UnsafeKVExternalSorter.java
+++ b/sql/core/src/main/java/org/apache/spark/sql/execution/UnsafeKVExternalSorter.java
@@ -242,7 +242,10 @@ public int compare(Object baseObj1, long baseOff1, Object baseObj2, long baseOff
       // into the row.
       row1.pointTo(baseObj1, baseOff1 + 4, -1);
       row2.pointTo(baseObj2, baseOff2 + 4, -1);
-      return ordering.compare(row1, row2);
+      int comparison = ordering.compare(row1, row2);
+      row1.pointTo(null, 0L, -1);
+      row2.pointTo(null, 0L, -1);
+      return comparison;
     }
   }