PERF: optimise type lookup to avoid invoking procs

2 files changed, 32 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 6310d70192..d3e5b0a4ad 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -431,16 +431,22 @@ module ActiveRecord
       private
 
         def get_oid_type(oid, fmod, column_name, sql_type = '') # :nodoc:
-          if !type_map.key?(oid)
+
+          result = type_map.fetch(oid, fmod, sql_type) {
+            nil
+          }
+
+          unless result
             load_additional_types(type_map, [oid])
+            result = type_map.fetch(oid, fmod, sql_type) {
+              warn "unknown OID #{oid}: failed to recognize type of '#{column_name}'. It will be treated as String."
+              Type::Value.new.tap do |cast_type|
+                type_map.register_type(oid, cast_type)
+              end
+            }
           end
 
-          type_map.fetch(oid, fmod, sql_type) {
-            warn "unknown OID #{oid}: failed to recognize type of '#{column_name}'. It will be treated as String."
-            Type::Value.new.tap do |cast_type|
-              type_map.register_type(oid, cast_type)
-            end
-          }
+          result
         end
 
         def initialize_type_map(m) # :nodoc:
diff --git a/activerecord/lib/active_record/type/hash_lookup_type_map.rb b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
index bf92680268..2a146d38a9 100644
--- a/activerecord/lib/active_record/type/hash_lookup_type_map.rb
+++ b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
@@ -1,6 +1,12 @@
 module ActiveRecord
   module Type
     class HashLookupTypeMap < TypeMap # :nodoc:
+
+      def initialize
+        @cache = {}
+        super
+      end
+
       delegate :key?, to: :@mapping
 
       def lookup(type, *args)
@@ -8,12 +14,24 @@ module ActiveRecord
       end
 
       def fetch(type, *args, &block)
-        @mapping.fetch(type, block).call(type, *args)
+        cache = (@cache[type] ||= {})
+        resolved = cache[args]
+
+        unless resolved
+          resolved = cache[args] = @mapping.fetch(type, block).call(type, *args)
+        end
+
+        resolved
       end
 
       def alias_type(type, alias_type)
         register_type(type) { |_, *args| lookup(alias_type, *args) }
       end
+
+      def register_type(key, value=nil, &block)
+        @cache = {}
+        super(key, value, &block)
+      end
     end
   end
 end