MySQL DB Availability

Starting/ Stopping MySQL

Starting MySQL:

• Run the mysqld binary directly.
• Run mysqld_safe.
• Run mysql.server with a parameter.
  • Includes copies such as /etc/init.d/mysql
  • Example (upstart/SysV init): service mysql start
  • Example (systemd): systemctl start mysql
• Use systemctl command for MySQL rpm installation for systemd distribution :
• systemctl start mysqld
• On Windows, start by mysqld.exe

Stopping MySQL:

• Kill the mysqld binary with the SIGTERM signal (-15).
• Kill mysqld_safe first if it is running.
• Run mysql.server with the parameter value stop.
• service mysql stop
• systemctl stop mysql
• Use systemctl command for MySQL rpm installation for systemd distribution :
• systemctl stop mysqld
• Stopping MySQL with mysqladmin (client login path): mysqladmin shutdown
• Sometimes mysqladmin commands need root privileges to run, hence you can also use
• (shutdown with credential ) mysqladmin -u root -p -h dbhost -P 3306 shutdown
• (shutdown with admin login path) mysqladmin --login-path=mysql shutdown

Using kill

• The service mysql stop command (or systemctl stop mysql on systemd
• distributions) sends the UNIX SIGTERM signal (kill -15) to the mysqld process which the
• process interprets as an instruction to shut down the server.
• When you use mysqladmin to shutdown, it uses a server protocol command to send the “shut down” message to the server. In both cases, the server process receives the message and performs the same orderly shutdown procedure.
• If you send the SIGKILL signal (kill -9), mysqld shuts down immediately without an
• orderly shutdown, as if you had pulled the power cord on the machine. If the mysqld_safe
• helper program is running, it detects this sudden shutdown as a crash and restarts mysqld.

MySQL Availability- Status Check

mysqladmin -u root -p status

If DB is up, it will show uptime and number of queries, etc.

Uptime: 1408 Threads: 1 Questions: 35 Slow queries: 0 Opens: 1 Flush tables: 2 Open tables: 27 Queries per second avg: 0.024

else, the error as follows

mysqladmin: connect to server at 'localhost' failed

error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'

Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!

Ps -ef|grep mysqld