jackc/pgx · error

unknown format code %d

Error message

unknown format code %d

What it means

Error "unknown format code %d" thrown in jackc/pgx.

Source

Thrown at pgtype/composite.go:221

	}

	return nil
}

func (c *CompositeCodec) DecodeDatabaseSQLValue(m *Map, oid uint32, format int16, src []byte) (driver.Value, error) {
	if src == nil {
		return nil, nil
	}

	switch format {
	case TextFormatCode:
		return string(src), nil
	case BinaryFormatCode:
		buf := make([]byte, len(src))
		copy(buf, src)
		return buf, nil
	default:
		return nil, fmt.Errorf("unknown format code %d", format)
	}
}

func (c *CompositeCodec) DecodeValue(m *Map, oid uint32, format int16, src []byte) (any, error) {
	if src == nil {
		return nil, nil
	}

	switch format {
	case TextFormatCode:
		scanner := NewCompositeTextScanner(m, src)
		values := make(map[string]any, len(c.Fields))
		for i := 0; scanner.Next() && i < len(c.Fields); i++ {
			var v any
			fieldPlan := m.PlanScan(c.Fields[i].Type.OID, TextFormatCode, &v)
			if fieldPlan == nil {
				return nil, fmt.Errorf("unable to scan OID %d in text format into %v", c.Fields[i].Type.OID, v)
			}

View on GitHub (pinned to ec1a0befd2)

When it happens

Trigger: Thrown at pgtype/composite.go:221 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of jackc/pgx@ec1a0befd2 (2026-08-04). Data as JSON: /data/errors/2016675c29a44d4f.json. Report an issue: GitHub.