[SPARK-14346][SQL] Lists unsupported Hive features in SHOW CREATE TABLE output

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/catalog/interface.scala

@@ -80,11 +80,8 @@ case class CatalogTablePartition(
  * Note that Hive's metastore also tracks skewed columns. We should consider adding that in the
  * future once we have a better understanding of how we want to handle skewed columns.
  *
- * @param hasUnsupportedFeatures is used to indicate whether all table metadata entries retrieved
- *        from the concrete underlying external catalog (e.g. Hive metastore) are supported by
- *        Spark SQL. For example, if the underlying Hive table has skewed columns, this information
- *        can't be mapped to [[CatalogTable]] since Spark SQL doesn't handle skewed columns for now.
- *        In this case `hasUnsupportedFeatures` is set to true. By default, it is false.
+ * @param unsupportedFeatures is a list of string descriptions of features that are used by the
+ *        underlying table but not supported by Spark SQL yet.
  */
 case class CatalogTable(
     identifier: TableIdentifier,
@@ -102,7 +99,7 @@ case class CatalogTable(
     viewOriginalText: Option[String] = None,
     viewText: Option[String] = None,
     comment: Option[String] = None,
-    hasUnsupportedFeatures: Boolean = false) {
+    unsupportedFeatures: Seq[String] = Seq.empty) {
 
   // Verify that the provided columns are part of the schema
   private val colNames = schema.map(_.name).toSet

sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala

@@ -633,16 +633,16 @@ case class ShowCreateTableCommand(table: TableIdentifier) extends RunnableComman
   }
 
   private def showCreateHiveTable(metadata: CatalogTable): String = {
-    def reportUnsupportedError(): Unit = {
-      throw new UnsupportedOperationException(
+    def reportUnsupportedError(features: Seq[String]): Unit = {
+      throw new AnalysisException(
         s"Failed to execute SHOW CREATE TABLE against table ${metadata.identifier.quotedString}, " +
-          "because it contains table structure(s) (e.g. skewed columns) that Spark SQL doesn't " +
-          "support yet."
+          "which is created by Hive and uses the following unsupported feature(s)\n" +
+          features.map(" - " + _).mkString("\n")
       )
     }
 
-    if (metadata.hasUnsupportedFeatures) {
-      reportUnsupportedError()
+    if (metadata.unsupportedFeatures.nonEmpty) {
+      reportUnsupportedError(metadata.unsupportedFeatures)
     }
 
     val builder = StringBuilder.newBuilder
@@ -651,7 +651,7 @@ case class ShowCreateTableCommand(table: TableIdentifier) extends RunnableComman
       case EXTERNAL => " EXTERNAL TABLE"
       case VIEW => " VIEW"
       case MANAGED => " TABLE"
-      case INDEX => reportUnsupportedError()
+      case INDEX => reportUnsupportedError(Seq("index table"))
     }
 
     builder ++= s"CREATE$tableTypeString ${table.quotedString}"

sql/hive/src/main/scala/org/apache/spark/sql/hive/client/HiveClientImpl.scala

@@ -337,10 +337,19 @@ private[hive] class HiveClientImpl(
       val schema = h.getCols.asScala.map(fromHiveColumn) ++ partCols
 
       // Skew spec, storage handler, and bucketing info can't be mapped to CatalogTable (yet)
-      val hasUnsupportedFeatures =
-        !h.getSkewedColNames.isEmpty ||
-          h.getStorageHandler != null ||
-          !h.getBucketCols.isEmpty
+      val unsupportedFeatures = ArrayBuffer.empty[String]
+
+      if (!h.getSkewedColNames.isEmpty) {
+        unsupportedFeatures += "skewed columns"
+      }
+
+      if (h.getStorageHandler != null) {
+        unsupportedFeatures += "storage handler"
+      }
+
+      if (!h.getBucketCols.isEmpty) {
+        unsupportedFeatures += "bucketing"
+      }
 
       CatalogTable(
         identifier = TableIdentifier(h.getTableName, Option(h.getDbName)),
@@ -369,7 +378,7 @@ private[hive] class HiveClientImpl(
         properties = h.getParameters.asScala.toMap,
         viewOriginalText = Option(h.getViewOriginalText),
         viewText = Option(h.getViewExpandedText),
-        hasUnsupportedFeatures = hasUnsupportedFeatures)
+        unsupportedFeatures = unsupportedFeatures)
     }
   }
 

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

@@ -17,7 +17,7 @@
 
 package org.apache.spark.sql.hive
 
-import org.apache.spark.sql.QueryTest
+import org.apache.spark.sql.{AnalysisException, QueryTest}
 import org.apache.spark.sql.catalyst.TableIdentifier
 import org.apache.spark.sql.catalyst.catalog.CatalogTable
 import org.apache.spark.sql.hive.test.TestHiveSingleton
@@ -247,7 +247,7 @@ class ShowCreateTableSuite extends QueryTest with SQLTestUtils with TestHiveSing
     }
   }
 
-  test("hive bucketing not supported") {
+  test("hive bucketing is not supported") {
     withTable("t1") {
       createRawHiveTable(
         s"""CREATE TABLE t1 (a INT, b STRING)
@@ -257,9 +257,11 @@ class ShowCreateTableSuite extends QueryTest with SQLTestUtils with TestHiveSing
          """.stripMargin
       )
 
-      intercept[UnsupportedOperationException] {
+      val cause = intercept[AnalysisException] {
         sql("SHOW CREATE TABLE t1")
       }
+
+      assert(cause.getMessage.contains(" - bucketing"))
     }
   }