Increase the MySQL max connections

The max_connections system variable sets the maximum permitted number of simultaneous client connections.

If you are seeing “Too many connections” errors, increasing the max_connections may help resolve the problem.

It is important to monitor server resource usage before and after adjusting max_connections. Increasing the maximum connections will result in higher memory usage.

In MySQL 8.0, the default value is 151 and the maximum is 100,000.

You can use ServerPilot’s MySQL monitoring dashboards to know whether you need to increase the value of max_connections.

Note

Regardless of the configured value for max_connections, the maximum number of connections will also be limited by the open files limit.

Change the MySQL max_connections setting

Create the file:

/etc/mysql/conf.d/max_connections.cnf

with the following contents (replace VALUE with the desired size).

/etc/mysql/conf.d/max_connections.cnf

[mysqld]
max_connections = VALUE

For example, the following sets the maximum connections to 300.

/etc/mysql/conf.d/max_connections.cnf

[mysqld]
max_connections = 300

After creating the file, restart MySQL.

sudo service mysql restart

Confirm the new value with the following command:

sudo mysql -e "SHOW VARIABLES LIKE 'max_connections';"