wait_timeout – The number of seconds that the server waits for activity in a non-interactive connection before closing it.
At the time of connection, wait_timeout is taken from the global value wait_timeout or interactive_timeout depending on the client type (as defined by the CLIENT_INTERACTIVE connect option for mysql_real_connect ())
Connect to MySQL and see the current value:
mysql -u USER -p show variables like "wait_timeout"; show variables like "interactive_timeout"; quit;
By default, the values wait_timeout and interactive_timeout are 28800 seconds = 8 hours.
You can set minimum 1, maximum – 31536000, maximum (for Windows) – 2147483.
You can change the value of wait_timeout by executing the SQL query, for example:
set global wait_timeout = 28800; set global interactive_timeout = 28800;
That the set value has not been reset, it needs to be specified in the file /etc/mysql/my.cnf, in the mysqld block:
[mysqld] wait_timeout = 28800 interactive_timeout = 28800