Note: It is good practice to back up your data before installing any new version of software. Although MySQL has done its best to ensure a high level of quality, you should protect your data by making a backup. MySQL generally recommends that you dump and reload your tables from any previous version to upgrade to 5.0.
Additionaly -Use this howto at your own risk !.
Before beginning to upgrade mysql ,you must understand that the php-mysql module in your system is compiled against the already installed mysql library and upgrading mysql will break the module !.
So first thing you must do is ensure you can create or actually recreate the mysql.so php module.you can either get it compiled by recompiling php in full or recompile the mysql.so alone and i should say the second is the best option
This can be a generic instruction ;but i have done this only on a Plesk 9 powered server.
Download the php source code matching your exact installed version. You can obtain this by installing the .src.rpm and changing to the SOURCES sub directory in /usr/src/redhat
change to the mysql support source directory of your php installation source
cd ext/mysql
==================
./phpize
./configure
make
==================
If the above steps go fine you are on the safe side.
Get the latest MySQL community server from http://dev.mysql.com/downloads/ . It is easy to install the rpm package if you are on a rpm based distro
Once mysql is installed,change to php’s ext/mysql directory again.Issue a
make clean
and run the mysql module compilation steps again
This time run
make install
in the end
Thats it.restart apache and mysql and check if we have any problems
In my case the startup script obtained from the mysql rpms were not working correctly
You can save the redhat init script (/etc/init.d/mysqld ) for use in such cases
If you have doubts contact me at anoop[at]gnusys[dot]net
