I was trying to install mysql 5 in Fedora Core 4, I cannot recall the version but probably it was 5.0.19. The installation went off smoothly but mysql wouldn't start up. Then I figured out that it was due to selinux and after disabling it mysql would start working.
In contrast Fedora Core 5 is very fast and mysql 5.0.18 comes packaged with it. It works flawlessly in FC 5.