jackc/pgx · error

invalid message length: %d

Error message

invalid message length: %d

What it means

Error "invalid message length: %d" thrown in jackc/pgx.

Source

Thrown at pgproto3/backend.go:181

		return &b.gssEncRequest, nil
	default:
		return nil, fmt.Errorf("unknown startup message code: %d", code)
	}
}

// Receive receives a message from the frontend. The returned message is only valid until the next call to Receive.
func (b *Backend) Receive() (FrontendMessage, error) {
	if !b.partialMsg {
		header, err := b.cr.Next(5)
		if err != nil {
			return nil, translateEOFtoErrUnexpectedEOF(err)
		}

		b.msgType = header[0]

		msgLength := int(int32(binary.BigEndian.Uint32(header[1:])))
		if msgLength < 4 {
			return nil, fmt.Errorf("invalid message length: %d", msgLength)
		}

		b.bodyLen = msgLength - 4
		if b.maxBodyLen > 0 && b.bodyLen > b.maxBodyLen {
			return nil, &ExceededMaxBodyLenErr{b.maxBodyLen, b.bodyLen}
		}
		b.partialMsg = true
	}

	var msg FrontendMessage
	switch b.msgType {
	case 'B':
		msg = &b.bind
	case 'C':
		msg = &b._close
	case 'D':
		msg = &b.describe
	case 'E':

View on GitHub (pinned to ec1a0befd2)

When it happens

Trigger: Thrown at pgproto3/backend.go:181 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/d844055d90d8f5b7.json. Report an issue: GitHub.