Resolution

Plesk 7.5.x  installs two instances of MySQL server:

a) MySQL server as the database provider of Plesk that stores Plesk configuration and clients/domains settings. It is located in %plesk_dir%MySQL and uses port 8306 to establish connections. It can be updated only to the latest version in 4.x.x series of MySQL.

To update Plesk  MySQL Database provider the following steps need to be completed:

1. Download the latest stable version of MySQL 4.x.x series

2. Stop Plesk SQL Server service.

3. Rename or backup the  %plesk_dir%mysql folder

4. Create the folder %plesk_dir%mysql and unpack downaloded mysql pack into this folder.

5. Delete the folder %plesk_dir%mysql\data.

6. Copy folder data from original (backed up) mysql to %plesk_dir%mysql.
 
7. Restart Plesk SQL Server service.


b) MySQL server database engine for client databases. It's located in %plesk_dir%databases\MySQL and uses port 3306 for connections. It can be updated to any latest stable version of MySQL.

To update the client MySQL server one needs to follow these steps:
1. Download the latest stable version of MySQL

2. Stop MySQL Server service.

3. Rename or backup the folder %plesk_dir%databases\mysql.

4. Create the folder %plesk_dir%databases\mysql and unpack downaloded mysql pack to this folder.

5. Delete the folder %plesk_dir%databases\mysql\data.

6. Copy the folder data from the original (backed up) mysql to %plesk_dir%databases\mysql.

7. Restart MySQL Server service.