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From Zhemzhitsky Sergey <Sergey_Zhemzhit...@sberbank-cib.ru>
Subject RE: We've got an App for that .... Qpid Web Based GUI - and more - just released.
Date Fri, 08 Feb 2013 10:48:41 GMT
Hello Frase,

Thanks a lot for clarification!

>> Hope it's not a show-stopper for you.
Of course it's not a show-stopper.

I've played a little bit with firebug and here is what it's writing on the msgDepth page

TypeError: stats.get(...) is undefined
while ((stats.get(i)[TIMESTAMP] < minimumTimestamp) && (i < limit)) i++;

I've debugged a little bit and found the following:

1. msgDepth stats is not a rate stats

var isRate = (description == "msgDepth") ? false : true

2. Next limit=size for a not rate stats

var limit = isRate ? size - 1 : size

3.  Then if we look at

while ((stats.get(i)[TIMESTAMP] < minimumTimestamp) && (i < limit)) i++;

the first part of the while loop condition will be executed twice (i=0, i=1) for limit=size=1
and i=0
so, for i=1 and size=1, stats.get(i) is undefined

What we have to do is to reorder the while loop conditions and everything will be fine, i.e.

while ((i < limit) && (stats.get(i)[TIMESTAMP] < minimumTimestamp)) i++;

Best Regards,

-----Original Message-----
From: Fraser Adams [mailto:fraser.adams@blueyonder.co.uk] 
Sent: Wednesday, February 06, 2013 11:58 PM
To: users@qpid.apache.org
Subject: Re: We've got an App for that .... Qpid Web Based GUI - and more - just released.

>>> Is it just msgDepth or do you see the same for msgTotalEnqueues 
>>> msgTotalDequeues too
> msgDepth only (event with 1.1 version). All the other pages work pretty fine.
> Best Regards,
> Sergey
Thanks for the clarification I've got a hunch about it..... In the graphs page JavaScript
there's a line that goes:

while((stats.get(i)[TIMESTAMP] < minimumTimestamp) && (i < limit)) i++;

ISTR having intermittent issues with that a while back, though TBH it was *really* infrequent
on my set up so I forgot about it. I'd be willing to bet it's that line that's the cause of
the problem you're seeing, though given the infrequency for me quite the scenario that causes
that condition I'm less sure on, I'll spend a bit of time trying to consistently break it.

I could put a bit more defensive code around it, almost certainly it's
get(...) returning with null, but I'd rather figure out the cause first than just defend against
the symptom.

I *hate* bugs like that, it's like it'll take me ten minutes to fix after I've spent two days
trying to reproduce it :-) c'est la vie

Hope it's not a show-stopper for you.


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