????MySQL??????????к?????????????????????????Щ??????????????????汾?MySQL 5.6?????????????????????????
????1?????mysqld????????MySQL????
????mysqld??MySQL???????????????????mysqld??????????MySQL????????mysqld?? MySQL 5.6????????????????????
????mysqld?? also known as MySQL Server?? is the main program that does most of the work in a MySQL installation. MySQL Server manages access to the MySQL data directory that contains databases and tables. The data directory is also the default location for other information such as log files and status files.
????When MySQL server starts?? it listens for network connections from client programs and manages access to databases on behalf of those clients.
????The mysqld program has many options that can be specified at startup. For a complete list of options?? run this command:
????shell> mysqld --verbose --help
????MySQL Server also has a set of system variables that affect its operation as it runs. System variables can be set at server startup?? and many of them can be changed at runtime to effect dynamic server reconfiguration. MySQL Server also has a set of status variables that provide information about its operation. You can monitor these status variables to access runtime performance characteristics.
???????MySQL??rpm???????????mysqldλ??/usr/sbin?￡????MySQL??????????????mysqld??λ??bin?????檔
[root@localhost ~]# whereis mysqld
mysqld: /usr/sbin/mysqld /usr/share/man/man8/mysqld.8.gz
[root@localhost ~]# /usr/sbin/mysqld stop
2016-06-27 14:52:54 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-06-27 14:52:54 9315 [ERROR] Fatal error: Please read "Security" section of the manual to find out how to run mysqld as root!
2016-06-27 14:52:54 9315 [ERROR] Aborting
2016-06-27 14:52:54 9315 [Note] Binlog end
2016-06-27 14:52:54 9315 [Note] /usr/sbin/mysqld: Shutdown complete
[root@localhost ~]# /usr/sbin/mysqld start
2016-06-27 14:52:59 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-06-27 14:52:59 9316 [ERROR] Fatal error: Please read "Security" section of the manual to find out how to run mysqld as root!
2016-06-27 14:52:59 9316 [ERROR] Aborting
2016-06-27 14:52:59 9316 [Note] Binlog end
2016-06-27 14:52:59 9316 [Note] /usr/sbin/mysqld: Shutdown complete
????2?????mysqld_safe????????MySQL????
??????????????????mysqld??mysqld_safe??????. ???mysqld_safe?????????????????????????????MySQL??????????????????????mysqld??????????MySQL????????mysqld_safe??????ο???????mysqld_safe — MySQL Server Startup Script