From 23d82c5278e209ef0051174834b32cd6ca8c3bb7 Mon Sep 17 00:00:00 2001
From: Andrew Or <andrew@databricks.com>
Date: Thu, 5 May 2016 17:12:56 -0700
Subject: [PATCH] Expose it

---
 .../main/scala/org/apache/spark/sql/catalog/Catalog.scala | 8 ++++++++
 .../scala/org/apache/spark/sql/internal/CatalogImpl.scala | 7 +++++++
 2 files changed, 15 insertions(+)

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala b/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala
index 7a815c1f99336..6aa89f81a577c 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala
@@ -27,6 +27,14 @@ import org.apache.spark.sql.types.StructType
  */
 abstract class Catalog {
 
+  /**
+   * Return an identifier for the underlying catalog implementation, currently must be
+   * either 'hive' or 'in-memory'.
+   *
+   * @since 2.0.0
+   */
+  def implementation: String
+
   /**
    * Returns the current default database in this session.
    *
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala b/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala
index 976c9c53de139..40122ef66e535 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala
@@ -21,6 +21,7 @@ import scala.collection.JavaConverters._
 import scala.reflect.runtime.universe.TypeTag
 
 import org.apache.spark.annotation.Experimental
+import org.apache.spark.internal.config.CATALOG_IMPLEMENTATION
 import org.apache.spark.sql.{AnalysisException, DataFrame, Dataset, SparkSession}
 import org.apache.spark.sql.catalog.{Catalog, Column, Database, Function, Table}
 import org.apache.spark.sql.catalyst.{DefinedByConstructorParams, TableIdentifier}
@@ -58,6 +59,12 @@ class CatalogImpl(sparkSession: SparkSession) extends Catalog {
     new Dataset[T](sparkSession, queryExecution, enc)
   }
 
+  /**
+   * Return an identifier for the underlying catalog implementation, currently must be
+   * either 'hive' or 'in-memory'.
+   */
+  override val implementation: String = sparkSession.sparkContext.conf.get(CATALOG_IMPLEMENTATION)
+
   /**
    * Returns the current default database in this session.
    */