Fix code review

Author: zuotingbing

sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/InsertIntoHiveTable.scala

@@ -104,8 +104,9 @@ case class InsertIntoHiveTable(
         inputPathName.substring(0, inputPathName.indexOf(stagingDir) + stagingDir.length)
       }
 
-    // SPARK-20594: The staging directory should be a child directory starts with "." to avoid
-    // being deleted if we set hive.exec.stagingdir under the table directory.
+    // SPARK-20594: This is a walk-around fix to resolve a Hive bug. Hive requires that the
+    // staging directory needs to avoid being deleted when users set hive.exec.stagingdir
+    // under the table directory.
     if (FileUtils.isSubDir(new Path(stagingPathName), inputPath, fs)
       && !stagingPathName.stripPrefix(inputPathName).stripPrefix(File.separator).startsWith(".")) {
       logDebug(s"The staging dir '$stagingPathName' should be a child directory starts " +

sql/hive/src/test/scala/org/apache/spark/sql/hive/InsertIntoHiveTableSuite.scala

@@ -495,44 +495,33 @@ class InsertIntoHiveTableSuite extends QueryTest with TestHiveSingleton with Bef
       }
   }
 
-  private def dropTables(tableNames: String*): Unit = {
-    tableNames.foreach { name =>
-      sql(s"DROP TABLE IF EXISTS $name")
-    }
-  }
-
   test(
-    """SPARK-20594: The staging directory should be appended with ".hive-staging"
-      |to avoid being deleted if we set hive.exec.stagingdir under the table directory
-      |without start with "."""".stripMargin) {
+    """SPARK-20594: This is a walk-around fix to resolve a Hive bug. Hive requires that the
+      |staging directory needs to avoid being deleted when users set hive.exec.stagingdir
+      |under the table directory.""".stripMargin) {
 
-    dropTables("test_table", "test_table1")
+    withTable("test_table", "test_table1") {
+      spark.range(1).write.saveAsTable("test_table")
 
-    sql("CREATE TABLE test_table (key int, value string)")
-
-    // Add some data.
-    testData.write.mode(SaveMode.Append).insertInto("test_table")
+      // Make sure the table has also been updated.
+      checkAnswer(
+        sql("SELECT * FROM test_table"),
+        Row(0)
+      )
 
-    // Make sure the table has also been updated.
-    checkAnswer(
-      sql("SELECT * FROM test_table"),
-      testData.collect().toSeq
-    )
+      sql("CREATE TABLE test_table1 (key int)")
 
-    sql("CREATE TABLE test_table1 (key int, value string)")
+      // Set hive.exec.stagingdir under the table directory without start with ".".
+      sql("set hive.exec.stagingdir=./test")
 
-    // Set hive.exec.stagingdir under the table directory without start with ".".
-    sql("set hive.exec.stagingdir=./test")
+      // Now overwrite.
+      sql("INSERT OVERWRITE TABLE test_table1 SELECT * FROM test_table")
 
-    // Now overwrite.
-    sql("INSERT OVERWRITE TABLE test_table1 SELECT * FROM test_table")
-
-    // Make sure the table has also been updated.
-    checkAnswer(
-      sql("SELECT * FROM test_table1"),
-      testData.collect().toSeq
-    )
-
-    dropTables("test_table", "test_table1")
+      // Make sure the table has also been updated.
+      checkAnswer(
+        sql("SELECT * FROM test_table1"),
+        Row(0)
+      )
+    }
   }
 }