Q I would like to upgrade from MySQL 3.23 to MySQL 4, but my Red Hat Enterprise Linux ES server does not have the relevant package available. I can see that a package is available from the MySQL site but I'm worried that it will break my server. Can you give me any advice on this job? I know how to do the actual install of the RPM - I just don't know what the consequences will be.
A The upgrade itself should pose no problems. However, please bear in mind that the RPM from MySQL will probably have a different username to those used by the Red Hat version, as well as some different paths. Any third-party programs you have that go into the MySQL 3.23 libraries may also need to be updated. The table structure between 3.23 and 4.x is totally compatible, but the MySQL table has a few extra columns that will need to be added. There is a script included in MySQL called mysql_fix_privilege_tables which should resolve any issues with this. One thing to think about before you go through with the upgrade is that Red Hat does not officially support MySQL 4 - so you'll lose all support for this aspect of your operating system. I've seen this combination work many times, but if you decide to go ahead don't forget to add MySQL to the up2date ignore list, or you will automatically downgrade to 3.23 next time up2date runs.