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/array_codec.go:375

func (spac *scanPlanArrayCodec) Scan(src []byte, dst any) error {
	c := spac.arrayCodec
	m := spac.m
	oid := spac.oid
	formatCode := spac.formatCode

	array := dst.(ArraySetter)

	if src == nil {
		return array.SetDimensions(nil)
	}

	switch formatCode {
	case BinaryFormatCode:
		return c.decodeBinary(m, oid, src, array)
	case TextFormatCode:
		return c.decodeText(m, oid, src, array)
	default:
		return fmt.Errorf("unknown format code %d", formatCode)
	}
}

func (c *ArrayCodec) 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)
	}

View on GitHub (pinned to ec1a0befd2)

When it happens

Trigger: Thrown at pgtype/array_codec.go:375 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/05ee4959b094a0b5.json. Report an issue: GitHub.