Nginx: logging full request data?

The log format can contain common variables, and variables that exist only at the time of a log write:

$bytes_sent the number of bytes sent to a client
$connection connection serial number
$connection_requests the current number of requests made through a connection
$msec time in seconds with a milliseconds resolution at the time of the log write $pipe “p” if request was pipelined, “.” otherwise
$request_length request length (including request line, header, and request body) $request_time request processing time in seconds with a milliseconds resolution; $status response status
$time_iso8601 local time in the ISO 8601 standard format
$time_local local time in the Common Log Format

RTFM!!!