diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 16f50fc594..64985ee933 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -328,8 +328,8 @@ module ActiveRecord
 
       def initialize_type_map(m) # :nodoc:
         super
-        m.register_type %r(datetime)i, Fields::DateTime.new
-        m.register_type %r(time)i,     Fields::Time.new
+        register_class_with_precision m, %r(datetime)i, Fields::DateTime
+        register_class_with_precision m, %r(time)i,     Fields::Time
       end
 
       def exec_without_stmt(sql, name = 'SQL') # :nodoc:
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 5a887ea529..b4fe7506f8 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -477,7 +477,6 @@ module ActiveRecord
           register_class_with_limit m, 'varbit', OID::BitVarying
           m.alias_type 'timestamptz', 'timestamp'
           m.register_type 'date', Type::Date.new
-          m.register_type 'time', Type::Time.new
 
           m.register_type 'money', OID::Money.new
           m.register_type 'bytea', OID::Bytea.new
@@ -503,10 +502,8 @@ module ActiveRecord
           m.alias_type 'lseg', 'varchar'
           m.alias_type 'box', 'varchar'
 
-          m.register_type 'timestamp' do |_, _, sql_type|
-            precision = extract_precision(sql_type)
-            OID::DateTime.new(precision: precision)
-          end
+          register_class_with_precision m, 'time', Type::Time
+          register_class_with_precision m, 'timestamp', OID::DateTime
 
           m.register_type 'numeric' do |_, fmod, sql_type|
             precision = extract_precision(sql_type)
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index f1f927852c..f2ba28a32f 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -46,7 +46,7 @@ def in_memory_db?
 end
 
 def mysql_56?
-  current_adapter?(:Mysql2Adapter) &&
+  current_adapter?(:MysqlAdapter, :Mysql2Adapter) &&
     ActiveRecord::Base.connection.send(:version).join(".") >= "5.6.0"
 end