2 files changed, 25 insertions, 10 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
index 35e699eeda..9b3de41fab 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
@@ -39,14 +39,14 @@ module ActiveRecord
           end
 
           def register_array_type(row)
-            if subtype = @store.lookup(row['typelem'].to_i)
-              register row['oid'], OID::Array.new(subtype, row['typdelim'])
+            register_with_subtype(row['oid'], row['typelem'].to_i) do |subtype|
+              OID::Array.new(subtype, row['typdelim'])
             end
           end
 
           def register_range_type(row)
-            if subtype = @store.lookup(row['rngsubtype'].to_i)
-              register row['oid'], OID::Range.new(subtype, row['typname'].to_sym)
+            register_with_subtype(row['oid'], row['rngsubtype'].to_i) do |subtype|
+              OID::Range.new(subtype, row['typname'].to_sym)
             end
           end
 
@@ -64,9 +64,13 @@ module ActiveRecord
             end
           end
 
-          def register(oid, oid_type)
-            oid = assert_valid_registration(oid, oid_type)
-            @store.register_type(oid, oid_type)
+          def register(oid, oid_type = nil, &block)
+            oid = assert_valid_registration(oid, oid_type || block)
+            if block_given?
+              @store.register_type(oid, &block)
+            else
+              @store.register_type(oid, oid_type)
+            end
           end
 
           def alias_type(oid, target)
@@ -74,6 +78,14 @@ module ActiveRecord
             @store.alias_type(oid, target)
           end
 
+          def register_with_subtype(oid, target_oid)
+            if @store.key?(target_oid)
+              register(oid) do |_, *args|
+                yield @store.lookup(target_oid, *args)
+              end
+            end
+          end
+
           def assert_valid_registration(oid, oid_type)
             raise ArgumentError, "can't register nil type for OID #{oid}" if oid_type.nil?
             oid.to_i
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 3a60de1f28..6ef47d8a11 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -516,9 +516,12 @@ module ActiveRecord
 
         def extract_limit(sql_type) # :nodoc:
           case sql_type
-          when /^bigint/i;    8
-          when /^smallint/i;  2
-          else super
+          when /^bigint/i, /^int8/i
+            8
+          when /^smallint/i
+            2
+          else
+            super
           end
         end