Miscellaneous Messages

Message	Direction	Description
BackendKeyData	Backend	Process ID and secret key for cancellation
NegotiateProtocolVersion	Backend	Protocol version negotiation
FunctionCall	Frontend	Server function invocation (legacy)
FunctionCallResponse	Backend	Function result
Terminate	Frontend	Close connection

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BackendKeyData

Sent during initialization. Provides the process ID and secret key needed to construct a CancelRequest on a separate connection.

Field	Type	Description
process_id	int	Backend process ID
secret_key	bytes	Secret key for CancelRequest (4 bytes for v3.0, variable for v3.2)

NegotiateProtocolVersion

Sent when the server does not support the exact protocol version or options requested by the client.

Field	Type	Description
newest_minor	int	Newest minor version supported by server
unrecognized	list[str]	Unrecognized protocol options

FunctionCall

Legacy server function invocation. Deprecated in favor of the extended query protocol.

Field	Type	Description
function_oid	int	Function OID
arg_formats	list[int]	Argument format codes
arguments	list[bytes \| None]	Argument values
result_format	int	Result format code

FunctionCallResponse

Result of a FunctionCall.

Field	Type	Description
result	bytes \| None	Function result (None if the function returned NULL)

Terminate

Gracefully close the connection. No fields.

from pygwire.messages import Terminate

msg = Terminate()
wire_bytes = msg.to_wire()