If you're me, you've probably done this at some point:

# dnf clean metadata
[...]
# dnf check-update
[... lists some available updates ...]

Then in another window, running as myself:

; dnf updateinfo info
[... doesn't report anything ...]

Wait, what?

What's going on here is that dnf maintains separate package databases for root and for individual users . When you run dnf as root, it consults (and updates) the 'official' DNF package databases and metadata under /var/cache/dnf . When you run dnf as any non-root user, it uses a /var/tmp/dnf-<user>-<random> directory instead; although everything in /var/cache/dnf is world-readable, dnf makes no attempt to look at it. As a result it's completely possible for root's dnf commands and your dnf commands to give completely different results.

You can reduce the odds of this by remembering to do ' dnf clean metadata ' or the like as yourself too, but this doesn't absolutely guarantee that root's data and your data are in sync. When your dnf command re-pulls the package information, it may fetch it from a different mirror that is more (or less) up to date than the mirror root's dnf used.

(And of course this wastes bandwidth on re-fetching data you already have.)

I hate the idea of running ' dnf updateinfo info ' as root instead of myself, but I'm probably going to have to get used to it. There are just too many annoyances otherwise.

PS: Yes, I know about ' dnf clean expire-cache '; I used to do it all the time with yum. Unlike with yum, with DNF it doesn't work really well to get me the latest update state. Have I mentioned that I'm not fond of DNF ?

Sidebar: How dnf should behave

When run as a normal user, DNF should try to use /var/cache/dnf data files if they're suitable, ie if they're sufficiently up to date and DNF is being used in a mode where it only needs read access to them. Only if DNF has been asked to do something that would normally write to /var/cache/dnf would it switch to the /var/tmp/dnf-<user>-... scheme. In other words, if you just used information commands as a normal user you'd get to take advantage of the system DNF database.