<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=us-ascii">
<META content="MSHTML 6.00.2900.5764" name=GENERATOR></HEAD>
<BODY>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff
size=2></FONT> </DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> bazaar-bounces@lists.canonical.com
[mailto:bazaar-bounces@lists.canonical.com] <B>On Behalf Of </B>Maritza
Mendez<BR><B>Sent:</B> Thursday, June 18, 2009 10:07 AM<BR><B>To:</B>
Bazaar<BR><B>Subject:</B> What should happen if bzr is unable to complete a
task?<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><BR>I've discussed this briefly with Alexander in the special context of
'bzr qbranch' in Bazaar Explorer, but there is a more general question I am
trying to express. Please help me find the best way to ask this
question.<BR><BR>I have a badly behaving set of computers at work.
Actually, I think the problem is with the subnet and our IT guys are working on
it. But meanwhile it has made me think about a more general
question. What we see is that a 'bzr branch' operation can hang if the
parent location is outside our firewall. Inside, no problem. At some
point, the progress bar freezes and nothing happens. I've waited at least
ten minutes in some cases. Nothing. In each case, we see that the
working directory has been created with the expected structure but no working
tree (obviously) and there is a .fetch file. We're able to determine that
the bzr process is still holding a handle to the fetch file, but the file has
stopped growing.<BR><BR>No problem: kill bzr and start over. The fact that
this happens more often than not for us is our problem. We have some
network problem that mysteriously affects bzr and (as far as we know) nothing
else. We're working on that.<BR><BR>But what about unattended
scripts? And what about the bzr-explorer and future tools which invoke bzr
(rather than calling bzrlib)? How should they recover if bzr stalls
because it can't get what it needs?<BR><SPAN class=921451016-18062009><FONT
face=Arial color=#0000ff size=2> </FONT></SPAN></DIV>
<DIV><SPAN class=921451016-18062009><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=921451016-18062009><FONT face=Arial color=#0000ff size=2>I've
had this exact thing happen. most recently yesterday :) The LSB
project has an autobuild scheme where seven different systems (some virtual
machines) build a whole load of stuff every night, and the builds of course
make sure they're using the latest code from our master bzr branches. In
five of the "machines" it turns out they're proximate - boxes sitting in the
same pair of racks in a data center as the server hosting the master branches
is, but t</FONT></SPAN><SPAN class=921451016-18062009><FONT face=Arial
color=#0000ff size=2>wo of the machines are contributed resources that are far
removed from our main machines, and are subject to periodic slowness - both
are big IBM machines where we're granted a virtual machine to work in, but
other things going in other virtual machines on may cause slowness due to
contention for finite resources, mainly network, and of course any such factors
are "external" to the VMs so we can't see what might be going
on.</FONT></SPAN></DIV>
<DIV><SPAN class=921451016-18062009><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=921451016-18062009><FONT face=Arial color=#0000ff size=2>Just
the last couple of days I was getting failure emails on one of these
that indicated a lock being held so an operation couldn't be performed.
Going in, I found a 57-hour-old "bzr branch" that was just "stuck". I
killed it, broke the locks, and everything's fine now - I didn't really
investigate as I'm so used to one transient or another messing up something in
the autobuilds, but why would a bzr branch just hang and never finish nor time
out? We certainly didn't have any way to recover from this automatically,
although now I'm aware of the issue I might put some sort of watchdog in
place.</FONT></SPAN></DIV>
<DIV><SPAN class=921451016-18062009><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV></BODY></HTML>