Which pages will this impact?

(In reply to Jason McDonald from comment #1)
> Which pages will this impact?

show_bug.cgi and enter_bug.cgi

I've been testing this and I don't think it's a bug. The extra cost appears to be connecting to the DB. The way this test is constructed a logged in user will already have a connection as they have accessed the profiles table, whereas a logged out user hasn't done that so needs to start up a connection.

I've timing around Bugzilla->dbh in sub get_enterable_products and running the tests as per https://bugzilla.mozilla.org/show_bug.cgi?id=1183492#c9

$ perl -Mlib=lib -MTime::HiRes -MBugzilla -MBugzilla::User -wE 'my $user = Bugzilla::User->new(1); $user->groups_as_string; my $t0 = Time::HiRes::time(); my $groups = $user->get_enterable_products; my $t1 = Time::HiRes::time(); say $t1 - $t0'
2.86102294921875e-06
0.0195839405059814

$ perl -Mlib=lib -MTime::HiRes -MBugzilla -MBugzilla::User -wE 'my $user = Bugzilla::User->new(0); $user->groups_as_string; my $t0 = Time::HiRes::time(); my $groups = $user->get_enterable_products; my $t1 = Time::HiRes::time(); say $t1 - $t0'
0.0166680812835693
0.0258760452270508

Bug was closed upstream after feedback above was posted there.