Symptoms
- Unable to start MySQL service or MySQL upgrade fails in Plesk for Windows.
-
One of the following errors can be found in
,
%plesk_dir%MySQLDataservername.errC:ParallelsInstallerautoinstaller3.log
or in the Event Viewer:[ERROR] C:Program FilesMySQLMySQL Server 5.6binmysqld.exe: unknown variable 'table_cache=256'
[ERROR] Aborting[ERROR] unknown variable 'key_buffer=256M'
[ERROR] Aborting
Cause
A declared variable is unknown in MySQL configuration.
Resolution
Disable the unknown variable in MySQL configuration file:
-
Connect to the server via RDP
-
Edit MySQL configuration file located in
%plesk_dir%DatabasesMySQLmy.ini
 with a text editor. -
Use ‘;‘ character to comment the following line. For example:
table_cache=256
It should look like:
;table_cache=256
-
Open Services MMC console Run > services.msc
-
Start the service MySQL Server > Right-click > Start
-
In case of the upgrade interruption, continue upgrading MySQL via Plesk GUI or with the following command:
C:> plesk installer –console
Additional Information:
For Linux –Â Unable to start MySQL: unknown variable table_cache