Merge pull request #10539 from davidcelis/ar-sql-improvements

Improve performance of ActiveRecord::Relation#blank?

activerecord/lib/active_record/relation.rb

@@ -21,6 +21,7 @@ class Relation
     alias :model :klass
     alias :loaded? :loaded
     alias :default_scoped? :default_scoped
+    alias :blank? :empty?
 
     def initialize(klass, table, values = {})
       @klass             = klass
@@ -575,11 +576,6 @@ def with_default_scope #:nodoc:
       end
     end
 
-    # Returns true if relation is blank.
-    def blank?
-      to_a.blank?
-    end
-
     def values
       Hash[@values]
     end