Bug#909804: Excessive CPU usage at system startup

[Josh Triplett]

Package: gnome-software
Version: 3.28.2-1
Severity: grave

I don't know whether the bug here lies in gnome-software, packagekit, or
some combination of the two.

Every time I start my system, I see packagekit burning a huge amount of
CPU for a minute, and this affects the performance of the system until
it stops.

Corresponding to this, I see a large number of log messages like this:
Sep 28 12:24:38 s PackageKit[717]: search-file transaction /18520_ddabdebb from uid 1000 finished with success after 643ms
Sep 28 12:24:39 s PackageKit[717]: search-file transaction /18521_bbebdedd from uid 1000 finished with success after 301ms

On my most recent system boot, I see 167 such messages, spanning nearly
a minute worth of 100% CPU.

-- System Information:
Debian Release: buster/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.18.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE=C.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gnome-software depends on:
ii  appstream                                    0.12.2-2
ii  apt-config-icons                             0.12.2-2
ii  dconf-gsettings-backend [gsettings-backend]  0.30.0-1
ii  gnome-software-common                        3.28.2-1
ii  gsettings-desktop-schemas                    3.28.1-1
ii  libappstream-glib8                           0.7.12-1
ii  libatk1.0-0                                  2.30.0-1
ii  libc6                                        2.27-6
ii  libcairo2                                    1.15.12-1
ii  libfwupd2                                    1.1.2-1
ii  libgdk-pixbuf2.0-0                           2.38.0+dfsg-6
ii  libglib2.0-0                                 2.58.1-2
ii  libgnome-desktop-3-17                        3.30.1-1
ii  libgspell-1-1                                1.6.1-1
ii  libgtk-3-0                                   3.24.0-3
ii  libgtk3-perl                                 0.034-2
ii  libgudev-1.0-0                               232-2
ii  libjson-glib-1.0-0                           1.4.2-4
ii  libpackagekit-glib2-18                       1.1.10-1
ii  libpolkit-gobject-1-0                        0.105-21
ii  libsecret-1-0                                0.18.6-3
ii  libsoup2.4-1                                 2.64.1-1
ii  packagekit                                   1.1.10-1
ii  software-properties-gtk                      0.96.20.2-1

gnome-software recommends no packages.

Versions of packages gnome-software suggests:
pn  apt-config-icons-hidpi         <none>
pn  fwupd                          <none>
pn  gnome-software-plugin-flatpak  <none>
pn  gnome-software-plugin-limba    <none>
pn  gnome-software-plugin-snap     <none>

-- no debconf information