[systemd-devel] -b switch fails where --since works

[Lennart Poettering]

On Wed, 10.08.16 09:29, Chris Murphy (lists at colorremedies.com) wrote:

> Hi,
> 
> I reported this against systemd-222-10.fc23.x86_64, but it's been a
> problem for longer than that, and it's still a problem in
> systemd-229-9.fc24.x86_64.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1294002
> 
> The gist is that -b switch works for a while, but then at some point
> it breaks and from that point it doesn't ever work again. By "doesn't
> work" I mean, the results are incomplete (dozen lines instead of
> thousands) and the wrong date (wrong boot entirely).
> 
> Meanwhile --since works fine, it's just a bit tedious to get back to a
> previous boot because I have to --list-boots first, and then
> copy/paste a date+time for --since.
> 
> I have no idea what breaks -b function, I'd guess it has something to
> do with inevitable journal file corruption and the -b code is getting
> confused where --since doesn't?

Most likely your system was rebooted/shutdown cleanly at a certain
point, and a journal file was synced incompletely and out-of-order,
which confuses the seeking code.

There has been quite some work to make journalctl handle that nicely
in v230, please try at least dc00966228ff90c554fd034e588ea55eb605ec52
and check if that makes things work for you. It's highly likely that
journalctl will start to just work for you if you update to that
version.

If this remains an issue even with current git or v231, please file a
bug and please provide me with the journal files that trigger this
behaviour, since there's little we can do otherwise.

Lennart

-- 
Lennart Poettering, Red Hat