Detect insertion error in DataSourceStrategy

Author: yjshen

sql/core/src/main/scala/org/apache/spark/sql/sources/DataSourceStrategy.scala

@@ -112,6 +112,12 @@ private[sql] object DataSourceStrategy extends Strategy with Logging {
       val mode = if (overwrite) SaveMode.Overwrite else SaveMode.Append
       execution.ExecutedCommand(InsertIntoHadoopFsRelation(t, query, mode)) :: Nil
 
+    case logical.InsertIntoTable(t, _, _, _, _) =>
+      throw new QueryPlanningException(s"""
+         | Attempt to insert into a RDD-based table: ${t.simpleString}, which is immutable.
+         | Save the RDD to a data source and register the data source as a table before insertion.
+       """.stripMargin)
+
     case _ => Nil
   }
 
@@ -393,3 +399,5 @@ private[sql] object DataSourceStrategy extends Strategy with Logging {
     filters.flatMap(translate)
   }
 }
+
+class QueryPlanningException(message: String) extends Exception(message)

sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala

@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql
 
+import org.apache.spark.sql.sources.QueryPlanningException
+
 import scala.language.postfixOps
 
 import org.apache.spark.sql.functions._
@@ -761,4 +763,25 @@ class DataFrameSuite extends QueryTest {
     assert(f.getMessage.contains("column3"))
     assert(!f.getMessage.contains("column2"))
   }
+
+  test("SPARK-6941: Better Error Message for inserting into RDD-based Table") {
+    val df = Seq(Tuple1(1)).toDF("col")
+    df.registerTempTable("rdd_base")
+
+    df.write.parquet("tmp_parquet")
+    val pdf = ctx.read.parquet("tmp_parquet")
+    pdf.registerTempTable("parquet_base")
+
+    df.write.json("tmp_json")
+    val jdf = ctx.read.json("tmp_json")
+    jdf.registerTempTable("json_base")
+
+    val insertion = Seq(Tuple1(2)).toDF("col")
+    val e = intercept[QueryPlanningException] {
+      insertion.write.insertInto("rdd_base")
+    }
+    assert(e.getMessage.contains("Attempt to insert into a RDD-based table"))
+    insertion.write.insertInto("parquet_base")
+    insertion.write.mode(SaveMode.Overwrite).insertInto("json_base")
+  }
 }