1 files changed, 4 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 87576abd92..0fc2b83b71 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -62,8 +62,10 @@ module ActiveRecord
             record.send(reflection.association_primary_key)
           end
         else
-          column  = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}"
-          scope.pluck(column)
+          @association_ids ||= (
+            column = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}"
+            scope.pluck(column)
+          )
         end
       end