comment for eliminate subqueries.

marmbrus · Jan 5, 2014 · 61b266f · 61b266f
1 parent d72a5a2
commit 61b266f
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/src/main/scala/catalyst/optimizer/Optimizer.scala b/src/main/scala/catalyst/optimizer/Optimizer.scala
@@ -11,6 +11,10 @@ object Optimize extends RuleExecutor[LogicalPlan] {
 
 }
 
+/**
+ * Removes subqueries from the plan.  Subqueries are only required to provide scoping information
+ * for attributes and can be removed once analysis is complete.
+ */
 object EliminateSubqueries extends Rule[LogicalPlan] {
   def apply(plan: LogicalPlan): LogicalPlan = plan transform {
     case Subquery(_, child) => child