Hi Vedrin,
 Could you please perform that scalability test with some concurrent
requests, using the following command:

curl -X POST -d
'dataset_uri=http://opentox.ntua.gr/ds.rdf&target=http://sth.com/feature/1' http://opentox.ntua.gr:3000/algorithm/mlr

I would like to know if you get an empty reply from the server (Status
Code 52) or if any other problems arise. I tried that at home using my
low speed connection so I can't flood the server with requests. 

* We could use 'ab' to perform scalability tests; it provides some
useful information. An example of use is:

ab -n 50000 -c 5  http://147.102.82.32:3000/algorithm/mlr

This will perform 50000 requests to the server (5 at the time)

Best Regards,
Pantelis

On Thu, 2009-12-31 at 16:43 +0200, Vedrin Jeliazkov wrote:
> Hi Pantelis, All,
> 
> 2009/12/30 chung <chvng at mail.ntua.gr>:
> 
> > When my RDF parser detects an empty string or a value that should be
> > numeric but cannot be cast as such, it overrides it and considers of it
> > to be missing. I'll try to fix that - I just need one more check in a
> > critical step of the RDF parsing, so I think it wont be very difficult.
> > The message "Can't Handle class attribute" (because the class attribute
> > is of type String) appears because there is some non-numeric entry for
> > the specified target feature which characterizes the whole feature as
> > String.
> 
> I just want to clarify that this error occurs (very) rarely and is
> difficult to reproduce. It might be exhibited only under periods of
> high load of the services (e.g. when they receive 10 consecutive
> requests for model training), though I'm not sure whether high load is
> the real trigger. However, it is important to keep in mind that the
> error occurs with the same dataset/feature URIs, for which in the
> majority of cases model training succeeds. So, perhaps, in this
> particular case, it is not due to any persistent (source) data issues,
> but has rather something to do with the way data is transmitted and/or
> processed at lower levels. The POST under load issue that Nina has
> solved with code migration to Noelios-Restlet/2.0m6 might be the
> culprit (I've noticed you're still using Noelios-Restlet/2.0m3),
> however this is just a (very) wild guess...
> 
> > Many issues will be fixed if we establish datatype declarations
> > for features.
> 
> Agreed -- in any case this is something we should discuss and decide
> upon during the next virtual meeting.
> 
> Best regards,
> Vedrin
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