[Pkg-shadow-devel] Bug#682156: delgroup I/O requirements are O(n^2) with regards to number of configured users

[Chris Hofstaedtler]

Control: tags -1 = wontfix confirmed upstream

On Fri, Jul 22, 2022 at 09:31:30PM +0200, Marc Haber wrote:
> this is a one decade old bug file against adduser, saying that the check
> done on group deletion to find out whether there is still a user having
> the to-be-deleted group as primary group, takes quite a long time if the
> system has many users.

[..]

> I am cloning and reassigning the clone to passwd to give you the
> possibility of investigating this in groupdel and probably implementing
> a more efficient way of doing this check.

groupdel does this:

| while ( ((pwd = prefix_getpwent ()) != NULL) && (pwd->pw_gid != gid) );

I don't see how this can become more efficient with the current
design of the NSS stack on Linux.

If anything, all NSS modules would need to provide a way of asking
this question in an efficient way.

Marking wontfix, as changing the NSS stack is not something I'm
going to pursue.

Chris