How to upgrade MySQL server from 5.1 to 5.5 on Linux?
The Plesk autoinstaller gets the packages from the base repositories of your OS. If MySQL 5.5 is not listed in base repository, it will not be available in Plesk autoinstaller.
If you want to upgrade MySQL version to 5.5, then you need to configure third party repository.
As an example, you can use Atomic repository to upgrade MySQL on RPM based systems:
wget -q -O - http://www.atomicorp.com/installers/atomic | sh yum upgrade mysql
Install MySQL packages:
# yum install mysql
Start MySQL service:
# service mysqld start
Upgrade MySQL databases:
# mysql_upgrade -uadmin -p`cat /etc/psa/.psa.shadow`
Note: PHP package may be also upgraded during this procedure. Oracle MySQL yum repository is not supported by Plesk.