Controls the format of messages written to the log file and which fields appear in them.
If the message string contains any of the following codes, the current values are substituted for the codes as each message is written.
The @ character.
Date and time that processing of the request started, unless the request could not be queued due to an error.
Date and time that the client connected.
Name of the database associated with the request.
Text of the error message, if an error occurred.
Date and time that processing of the request finished.
IP address of the client.
Length of the response, in bytes, including headers and body.
HTTP request method.
Listener port associated with the request.
Date and time that the request was queued for processing, unless the request could not be queued due to an error.
Status code and description of the HTTP response.
HTTP status code.
Date and time that the current log entry was written.
Requested URI.
Requested HTTP version.
Time taken to process the request (@F – @B), or 0.000 if the request was not processed due to an error.