diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/AttributeSet.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/AttributeSet.scala
index adaeab0b5c027..f951701610b16 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/AttributeSet.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/AttributeSet.scala
@@ -58,7 +58,8 @@ class AttributeSet private (val baseSet: Set[AttributeEquals])
 
   /** Returns true if the members of this AttributeSet and other are the same. */
   override def equals(other: Any) = other match {
-    case otherSet: AttributeSet => baseSet.map(_.a).forall(otherSet.contains)
+    case otherSet: AttributeSet =>
+      otherSet.size == baseSet.size && baseSet.map(_.a).forall(otherSet.contains)
     case _ => false
   }