Why can't I uninstall mysql completely? look! it's still there

Question

root@db2:/var/log/mysql# aptitude remove mysql-server --purge
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.
Writing extended state information... Done
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done

root@db2:/var/log/mysql# mysql
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

Answer 1

The mysql client comes from the appropriately named mysql-client package, which you didn't purge.

Edit: on the other hand, on my system, running the client gives a can't connect to local MySQL server error.

does ps auxwww | grep [m]ysql show any running processes? If so, what does /proc/$PID tell you about the process? Perhaps you installed the daemon from source at some point; perhaps the uninstaller didn't manage to kill the running process..

Answer 2

The package might have been removed, but the daemon apparently has not been stopped. As the daemon has all it's pages in memory and / or doesn't require it's libraries and binaries at the moment, it keeps on running. Funny thing is, you cannot stop it nicely now, because the rc scripts have been removed :)

Next time, stop a service before you remove it.

Now, reinstall it, stop it nicely, and purge the whole enchilada.