add_pg_decoders

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1107
        def add_pg_decoders
          @mapped_default_timezone = nil
          @timestamp_decoder = nil

          coders_by_name = {
            "int2" => PG::TextDecoder::Integer,
            "int4" => PG::TextDecoder::Integer,
            "int8" => PG::TextDecoder::Integer,
            "oid" => PG::TextDecoder::Integer,
            "float4" => PG::TextDecoder::Float,
            "float8" => PG::TextDecoder::Float,
            "numeric" => PG::TextDecoder::Numeric,
            "bool" => PG::TextDecoder::Boolean,
            "timestamp" => PG::TextDecoder::TimestampUtc,
            "timestamptz" => PG::TextDecoder::TimestampWithTimeZone,
          }
          coders_by_name["date"] = PG::TextDecoder::Date if decode_dates

          known_coder_types = coders_by_name.keys.map { |n| quote(n) }
          query = <<~SQL % known_coder_types.join(", ")
            SELECT t.oid, t.typname
            FROM pg_type as t
            WHERE t.typname IN (%(
          SQL
          result = internal_execute(query, "SCHEMA", [], allow_retry: true, materialize_transactions: false)
          coders = result.filter_map { |row| construct_coder(row, coders_by_name[row["typname"]]) }

          map = PG::TypeMapByOid.new
          coders.each { |coder| map.add_coder(coder) }
          @raw_connection.type_map_for_results = map

          @type_map_for_results = PG::TypeMapByOid.new
          @type_map_for_results.default_type_map = map
          @type_map_for_results.add_coder(PG::TextDecoder::Bytea.new(oid: 17, name: "bytea"))
          @type_map_for_results.add_coder(MoneyDecoder.new(oid: 790, name: "money"))

          # extract timestamp decoder for use in update_typemap_for_default_timezone
          @timestamp_decoder = coders.find { |coder| coder.name == "timestamp" }
          update_typemap_for_default_timezone
        end

        def construct_coder(row, coder_class)
          return unless coder_class
          coder_class.new(oid: row["oid"].to_i, name: row["typname"])
        end

        class MoneyDecoder < PG::SimpleDecoder # :nodoc:
          TYPE = OID::Money.new

          def decode(value, tuple = nil, field = nil)
            TYPE.deserialize(value)
          end
        end

        ActiveRecord::Type.add_modifier({ array: true }, OID::Array, adapter: :postgresql)
        ActiveRecord::Type.add_modifier({ range: true }, OID::Range, adapter: :postgresql)
        ActiveRecord::Type.register(:bit, OID::Bit, adapter: :postgresql)
        ActiveRecord::Type.register(:bit_varying, OID::BitVarying, adapter: :postgresql)
        ActiveRecord::Type.register(:binary, OID::Bytea, adapter: :postgresql)
        ActiveRecord::Type.register(:cidr, OID::Cidr, adapter: :postgresql)
        ActiveRecord::Type.register(:date, OID::Date, adapter: :postgresql)
        ActiveRecord::Type.register(:datetime, OID::DateTime, adapter: :postgresql)
        ActiveRecord::Type.register(:decimal, OID::Decimal, adapter: :postgresql)
        ActiveRecord::Type.register(:enum, OID::Enum, adapter: :postgresql)
        ActiveRecord::Type.register(:hstore, OID::Hstore, adapter: :postgresql)
        ActiveRecord::Type.register(:inet, OID::Inet, adapter: :postgresql)
        ActiveRecord::Type.register(:interval, OID::Interval, adapter: :postgresql)
        ActiveRecord::Type.register(:jsonb, OID::Jsonb, adapter: :postgresql)
        ActiveRecord::Type.register(:money, OID::Money, adapter: :postgresql)
        ActiveRecord::Type.register(:point, OID::Point, adapter: :postgresql)
        ActiveRecord::Type.register(:legacy_point, OID::LegacyPoint, adapter: :postgresql)
        ActiveRecord::Type.register(:uuid, OID::Uuid, adapter: :postgresql)
        ActiveRecord::Type.register(:vector, OID::Vector, adapter: :postgresql)
        ActiveRecord::Type.register(:xml, OID::Xml, adapter: :postgresql)
    end
    ActiveSupport.run_load_hooks(:active_record_postgresqladapter, PostgreSQLAdapter)
  end
end