I was getting complete freezes on my wife’s machine.
It would lock up both the GUI and ssh and needed a power cycle to get working again. It started getting quicker, so even after a restart it would stop the terminal or ssh session.
I tried an update and it froze on the first database.
I then went into the F2 terminal and stopped lightdm. At which point the system became stable and I could try and find out what was wrong.
The update left pacman with a locked db. I unlocked tried an upgrade and found that extra.db was corrupt. Updated the mirrors, and then when that was not enough renamed extra.db to extra-borked.db along with extra.files.
At that point the upgrade worked and everything has been running fast since.
The key point seemed to be not logging in to lightdm and thus triggering the pamac update manager to check things. Pacman threw large nos of Extra db tar corrupt when I tried running the upgrade via pacman once I had fixed the locking issue.
Looking at what happens from another machine via ssh after the login.
pamac-checkupdates runs after the login and uses 100% cpu on the now OK system. My assumption is that the corrupted extra db caused this to fail and hang the system.
journalclt was not particularly helpful in tracking down the cause of the errors.
Problem now seems to be resolved, but hopefully will help anyone with a system freeze in GUI on a previously stable system that now has problems with updating.
Notes:
16GB ram
No Swap
6 core dual thread