diff --git a/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala b/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala
index 497bd4826677..e11018fd15cf 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala
@@ -160,12 +160,19 @@ class DataFrame private[sql](
     }
   }
 
+  /**
+    * Compose the string representing rows for output
+    */
+  def showString(): String = {
+    showString(20);
+  }
+
   /**
    * Compose the string representing rows for output
    * @param _numRows Number of rows to show
    * @param truncate Whether truncate long strings and align cells right
    */
-  private[sql] def showString(_numRows: Int, truncate: Boolean = true): String = {
+  def showString(_numRows: Int, truncate: Boolean = true): String = {
     val numRows = _numRows.max(0)
     val sb = new StringBuilder
     val takeResult = take(numRows + 1)