This is a command-line option for the
mysqldump commands (arg: Optional).
This causes the binary log position and filename of the master to be appended to the dumped data output. Setting the value to 1, will printit as a CHANGE MASTER command in the dumped data output; if equal to 2, that command will be prefixed with a comment symbol. This option will turn --lock-all-tables on, unless --single-transaction is specified too (in which case a global read lock is only taken a short time at the beginning of the dump - don't forget to read about --single-transaction below). In all cases any action on logs will happen at the exact moment of the dump.Option automatically turns --lock-tables off.