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marmbrus · Feb 12, 2015 · d4e9015 · d4e9015
1 parent af9e668
commit d4e9015
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
@@ -78,6 +78,8 @@ class Analyzer(catalog: Catalog,
     def failAnalysis(msg: String) = { throw new AnalysisException(msg) }
 
     def apply(plan: LogicalPlan): LogicalPlan = {
+      // We transform up and order the rules so as to catch the first possible failure instead
+      // of the result of cascading resolution failures.
       plan.foreachUp {
         case operator: LogicalPlan =>
           operator transformAllExpressions {