[SQL] SPARK-1372 Support for caching and uncaching tables in a SQLContext.

This doesn't yet support different databases in Hive (though you can probably workaround this by calling `USE <dbname>`).  However, given the time constraints for 1.0 I think its probably worth including this now and extending the functionality in the next release.

Author: Michael Armbrust <michael@databricks.com>

Closes #282 from marmbrus/cacheTables and squashes the following commits:

83785db [Michael Armbrust] Support for caching and uncaching tables in a SQLContext.

1 files changed, 10 insertions, 1 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Catalog.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Catalog.scala
index e09182dd8d..6b58b9322c 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Catalog.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Catalog.scala
@@ -31,6 +31,7 @@ trait Catalog {
     alias: Option[String] = None): LogicalPlan
 
   def registerTable(databaseName: Option[String], tableName: String, plan: LogicalPlan): Unit
+  def unregisterTable(databaseName: Option[String], tableName: String): Unit
 }
 
 class SimpleCatalog extends Catalog {
@@ -40,7 +41,7 @@ class SimpleCatalog extends Catalog {
     tables += ((tableName, plan))
   }
 
-  def dropTable(tableName: String) = tables -= tableName
+  def unregisterTable(databaseName: Option[String], tableName: String) = { tables -= tableName }
 
   def lookupRelation(
       databaseName: Option[String],
@@ -87,6 +88,10 @@ trait OverrideCatalog extends Catalog {
       plan: LogicalPlan): Unit = {
     overrides.put((databaseName, tableName), plan)
   }
+
+  override def unregisterTable(databaseName: Option[String], tableName: String): Unit = {
+    overrides.remove((databaseName, tableName))
+  }
 }
 
 /**
@@ -104,4 +109,8 @@ object EmptyCatalog extends Catalog {
   def registerTable(databaseName: Option[String], tableName: String, plan: LogicalPlan): Unit = {
     throw new UnsupportedOperationException
   }
+
+  def unregisterTable(databaseName: Option[String], tableName: String): Unit = {
+    throw new UnsupportedOperationException
+  }
 }