Supplying Arel::SqlLiteral is much faster

activerecord/lib/active_record/relation.rb

@@ -282,8 +282,11 @@ def to_sql
 
     def scope_for_create
       @scope_for_create ||= begin
-        @create_with_value || wheres.inject({}) do |hash, where|
-          hash[where.operand1.name] = where.operand2.value if where.is_a?(Arel::Predicates::Equality)
+        @create_with_value || @where_values.inject({}) do |hash, where|
+          if where.is_a?(Arel::Predicates::Equality)
+            hash[where.operand1.name] = where.operand2.respond_to?(:value) ? where.operand2.value : where.operand2
+          end
+
           hash
         end
       end

activerecord/lib/active_record/relation/query_methods.rb

@@ -119,8 +119,16 @@ def build_arel
         end
       end
 
-      @where_values.uniq.each do |w|
-        arel = w.is_a?(String) ? arel.where(w) : arel.where(*w)
+      @where_values.uniq.each do |where|
+        next if where.blank?
+
+        case where
+        when Arel::SqlLiteral
+          arel = arel.where(where)
+        else
+          sql = where.is_a?(String) ? where : where.to_sql
+          arel = arel.where(Arel::SqlLiteral.new("(#{sql})"))
+        end
       end
 
       @having_values.uniq.each do |h|
@@ -135,7 +143,7 @@ def build_arel
       end
 
       @order_values.uniq.each do |o|
-        arel = arel.order(o) if o.present?
+        arel = arel.order(Arel::SqlLiteral.new(o.to_s)) if o.present?
       end
 
       selects = @select_values.uniq
@@ -169,8 +177,7 @@ def build_where(*args)
       builder = PredicateBuilder.new(table.engine)
 
       conditions = if [String, Array].include?(args.first.class)
-        sql = @klass.send(:sanitize_sql, args.size > 1 ? args : args.first)
-        Arel::SqlLiteral.new("(#{sql})") if sql.present?
+        @klass.send(:sanitize_sql, args.size > 1 ? args : args.first)
       elsif args.first.is_a?(Hash)
         attributes = @klass.send(:expand_hash_conditions_for_aggregates, args.first)
         builder.build_from_hash(attributes, table)