diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 3b4439fc4641761d37bbdc545510fba27e707d3a..b2af01ab5b8fb4eb8d8a51c0ee43dc7b0cd4c4c0 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -76,7 +76,7 @@ class PostgreSQLAdapter < AbstractAdapter
         primary_key: "bigserial primary key",
         string:      { name: "character varying" },
         text:        { name: "text" },
-        integer:     { name: "integer" },
+        integer:     { name: "integer", limit: 4 },
         float:       { name: "float" },
         decimal:     { name: "decimal" },
         datetime:    { name: "timestamp" },
@@ -439,9 +439,9 @@ def get_oid_type(oid, fmod, column_name, sql_type = "".freeze)
         end
 
         def initialize_type_map(m = type_map)
-          register_class_with_limit m, "int2", Type::Integer
-          register_class_with_limit m, "int4", Type::Integer
-          register_class_with_limit m, "int8", Type::Integer
+          m.register_type "int2", Type::Integer.new(limit: 2)
+          m.register_type "int4", Type::Integer.new(limit: 4)
+          m.register_type "int8", Type::Integer.new(limit: 8)
           m.register_type "oid", OID::Oid.new
           m.register_type "float4", Type::Float.new
           m.alias_type "float8", "float4"
@@ -508,17 +508,6 @@ def initialize_type_map(m = type_map)
           load_additional_types
         end
 
-        def extract_limit(sql_type)
-          case sql_type
-          when /^bigint/i, /^int8/i
-            8
-          when /^smallint/i
-            2
-          else
-            super
-          end
-        end
-
         # Extracts the value from a PostgreSQL column default definition.
         def extract_value_from_default(default)
           case default