feat: add option to enable Redshift OIDs

conn.go

@@ -87,6 +87,7 @@ type parameterStatus struct {
 	serverVersion                            int
 	currentLocation                          *time.Location
 	inHotStandby, defaultTransactionReadOnly sql.NullBool
+	isRedshift                               bool
 }
 
 type format int
@@ -1554,6 +1555,8 @@ func (cn *conn) processParameterStatus(r *readBuf) {
 	switch r.string() {
 	default:
 		// ignore
+	case "padb_version":
+		cn.parameterStatus.isRedshift = true
 	case "server_version":
 		var major1, major2 int
 		_, err := fmt.Sscanf(r.string(), "%d.%d", &major1, &major2)

rows.go

@@ -161,6 +161,11 @@ func (rs *rows) ColumnTypeScanType(index int) reflect.Type {
 
 // ColumnTypeDatabaseTypeName return the database system type name.
 func (rs *rows) ColumnTypeDatabaseTypeName(index int) string {
+	if rs.cn.parameterStatus.isRedshift {
+		if n, ok := redshiftTypeName[rs.colTyps[index].OID]; ok {
+			return n
+		}
+	}
 	return rs.colTyps[index].Name()
 }
 
@@ -243,3 +248,26 @@ func (fd fieldDesc) PrecisionScale() (precision, scale int64, ok bool) {
 		return 0, 0, false
 	}
 }
+
+var redshiftTypeName = map[oid.Oid]string{
+	86:   "PG_SHADOW",
+	87:   "PG_GROUP",
+	88:   "PG_DATABASE",
+	90:   "PG_TABLESPACE",
+	635:  "_SPECTRUM_ARRAY",
+	636:  "_SPECTRUM_MAP",
+	637:  "_SPECTRUM_STRUCT",
+	1188: "INTERVALY2M",
+	1189: "_INTERVALY2M",
+	1190: "INTERVALD2S",
+	1191: "_INTERVALD2S",
+	2935: "HLLSKETCH",
+	3000: "GEOMETRY",
+	3001: "GEOGRAPHY",
+	4000: "SUPER",
+	4600: "USERITEM",
+	4601: "_USERITEM",
+	4602: "ROLEITEM",
+	4603: "_ROLEITEM",
+	6551: "VARBYTE",
+}

rows_test.go

@@ -41,6 +41,41 @@ func TestDataTypeName(t *testing.T) {
 	}
 }
 
+func TestDataTypeNameRedshift(t *testing.T) {
+	tts := []struct {
+		typ  oid.Oid
+		name string
+	}{
+		{635, "_SPECTRUM_ARRAY"},
+		{636, "_SPECTRUM_MAP"},
+		{637, "_SPECTRUM_STRUCT"},
+		{4000, "SUPER"},
+	}
+
+	rs := &rows{
+		cn: &conn{
+			parameterStatus: parameterStatus{isRedshift: true},
+		},
+		rowsHeader: rowsHeader{
+			colTyps: []fieldDesc{},
+		},
+	}
+
+	for i, tt := range tts {
+		rs.colTyps = []fieldDesc{{OID: tt.typ}}
+		if name := rs.ColumnTypeDatabaseTypeName(0); name != tt.name {
+			t.Errorf("(%d) got: %s want: %s", i, name, tt.name)
+		}
+	}
+
+	// Without Redshift flag
+	rs.cn.parameterStatus.isRedshift = false
+	rs.colTyps = []fieldDesc{{OID: 635}}
+	if name := rs.ColumnTypeDatabaseTypeName(0); name != "" {
+		t.Errorf("got: %q want: %q", name, "") // 635 is not in standard types map, so it returns empty string
+	}
+}
+
 func TestDataType(t *testing.T) {
 	tts := []struct {
 		typ  oid.Oid