Improve == and hash methods on various schema cache structs to be allocation free.

The previous implementation would allocate 2 arrays per comparisons.

I tried relying on Struct, but they do allocate one Hash inside `Struct#hash`.

1 files changed, 5 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/mysql/type_metadata.rb b/activerecord/lib/active_record/connection_adapters/mysql/type_metadata.rb
index 7ad0944d51..56479f27bf 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/type_metadata.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/type_metadata.rb
@@ -16,19 +16,16 @@ module ActiveRecord
 
         def ==(other)
           other.is_a?(MySQL::TypeMetadata) &&
-            attributes_for_hash == other.attributes_for_hash
+            __getobj__ == other.__getobj__ &&
+            extra == other.extra
         end
         alias eql? ==
 
         def hash
-          attributes_for_hash.hash
+          TypeMetadata.hash ^
+            __getobj__.hash ^
+            extra.hash
         end
-
-        protected
-
-          def attributes_for_hash
-            [self.class, @type_metadata, extra]
-          end
       end
     end
   end