ErrorResponse An error has occurred. Processing of the query string is complete. A separate message is sent to indicate this because the query string may contain multiple SQL commands. ReadyForQuery will always be sent, whether processing terminates successfully or with an error. NoticeResponse A warning message has been issued in relation to the query.
Notices are in addition to other responses, ie.
A frontend must be prepared to accept ErrorResponse and NoticeResponse messages whenever it is expecting any other type of message. Actually, it is possible for NoticeResponse to arrive even when the frontend is not expecting any kind of message, that is, the backend is nominally idle. It is recommended that the frontend check for such asynchronous notices just before issuing any new command. Function Call A Function Call cycle is initiated by the frontend sending a FunctionCall message to the backend. The backend then sends one or more response messages depending on the results of the function call, and finally a ReadyForQuery response message.