In my testings the errors were actually 500 internal server errors,
not content length issues. These pages were dynamic in that they
returned information from the database, but it was always the exact
same 10 records. The content length was not one of the reported failed
requests types. I can even replicate this with the welcome app, just
add a friends table, and a sqltable on the default/index page, insert
some records, then run ab on the index page, it always return sthe
same thing, but will generate roughly 15% error ratios not related to
content length (since it stays the same)

--
Thadeus





On Thu, Aug 12, 2010 at 12:27 PM, mdipierro <mdipie...@cs.depaul.edu> wrote:
> I think I figure it. It is not a bug in web2py. The Content-Length is
> not computed by web2py but it is computed by the web server and it is
> computed correctly.
>
> The length is actually different at each request.
>
> This is because:
> 1) in forms it contains the CSRF token with is a uuid and is different
> at each request
> 2) forms that contain a date may have different rounding for seconds
> 3) pages with display [request], [response], etc also contain datetime
> info which have different length at every request
>
> The second link Jonathan posted says:
>
> "Quite often you may see in the statistics "Failed requests: 5" or
> similar, followed by a list of the types of failure: "(Connect: 0,
> Receive: 0, Length: 5, Exceptions: 0)". If the only type of failure
> that actually occurred is 'Length' then don't be alarmed. This simply
> means that each request (for the same URL) returned a different length
> response, which ab regards as suspicious. However it's perfectly
> normal for dynamic webpages, especially if they include the time or
> other very dynamic data on the page. "
>
> This our case.
>
> Case closed?
>
> Massimo
>
> On Aug 12, 12:00 pm, mdipierro <mdipie...@cs.depaul.edu> wrote:
>> You are the man.
>>
>> For the page I am considering the fail requests are not a real failure
>> but declare a content-length of 19383 (wrong) instead of 19384
>> (correct). Let's continue investigate...
>>
>> Massimo
>>
>> On Aug 12, 11:53 am, Jonathan Lundell <jlund...@pobox.com> wrote:
>>
>> > On Aug 12, 2010, at 8:44 AM, David Marko wrote:
>>
>> > > Failed requests:        19
>> > >   (Connect: 0, Receive: 0, Length: 19, Exceptions: 0)
>>
>> > Even more reassurance:
>>
>> >http://stackoverflow.com/questions/1512304/failed-requests-by-length-...
>>
>> >http://alwaysthecritic.typepad.com/atc/2009/04/apache-bench-notes.html
>>
>> > The length variation should be checked, of course, but it may well be 
>> > harmless.
>>
>> > If the length variation is under our control (cookie format, maybe?), 
>> > perhaps we could make an effort to make it the same.
>

Reply via email to