Inject the `PredicateBuilder` into the `Relation` instance

Construction of relations can be a hotspot, we don't want to create one
of these in the constructor. This also allows us to do more expensive
things in the predicate builder's constructor, since it's created once
per AR::Base subclass

1 files changed, 5 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 94d1e07069..65ca1f6fd3 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -248,10 +248,14 @@ module ActiveRecord
           end
       end
 
+      def predicate_builder # :nodoc:
+        @predicate_builder ||= PredicateBuilder.new(self, arel_table)
+      end
+
       private
 
       def relation #:nodoc:
-        relation = Relation.create(self, arel_table)
+        relation = Relation.create(self, arel_table, predicate_builder)
 
         if finder_needs_type_condition?
           relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)