[MOBY-dev] [moby] Moby services in Python

[Javier de la Torre]

No, ok, fine...

Is just that the software I am working on handle this thing in a
different way...
Our software is a retrieval service, it is actually a database
wrapper. With the protocol it works if you want to retrieve several
"objects", records, you do it by defining a query.

Still I think it will be ok to transform this. But I am gonna have to
implement some limitations on the number of invocations. If a user
send my service 10.000 records I will not handle all of them because
my service can easily die.

In theory if all the requested objects are of the same type, what they
must be because is one single service, I can transform it into a
single SQL statement to retrieve all of them at once. If I have to
lunch a different database query per object then I will be into
troubles...

Best regards,

Javier.


On 8/2/06, Paul Gordon <gordonp at ucalgary.ca> wrote:
> I have always been a champion of the multiple invocations requirement,
> and still am, for several reasons:
>
> 0. First we must acknowledge that people will want to run a bunch of
> data against a service.  I do already, and many Taverna workflows do to
> (implicit iterators).
>
> 1. Some services may use hardware accelerator, which can perform 100
> jobs as quick as 1 if they are submitted together.
>
> 2. If you have a cluster running the service, it is much easier to
> schedule 100 jobs efficiently than to receive 100 individual requests
> over the course of a few seconds.  i.e. division of labour is much
> easier when you know in advance how much there is to do!
>
> 3. If your server is running 1 CPU, you can decide to run the 100 jobs
> sequentially, at the pace you like (especially if you have many requests
> coming in from different users at the same time).  If the 100 jobs are
> submitted separately, it is the client (e.g. Taverna) that decides how
> much breathing room you have.  Encouraging
> multiple-invocations-in-one-envelope may reduce inadvertent
> denial-of-service attacks.
>
> 4. The network and computational overhead is much smaller for 1 large
> request than 100 small ones: 1 SOAP envelope vs. 100, 1 servlet
> invocation vs. 100, etc.
>
> 5. It's not hard to implement!  All you really need to do is add a for
> loop to the service code... MobyServlet
> (http://biomoby.open-bio.org/CVS_CONTENT/moby-live/Java/docs/deployingServices.html)
> supports multiple invocations implicitly, I don't even really tell the
> developer about it: their processRequest() method gets called for each
> mobyData block.
>
> My CAD 0.02,
>
> Paul
> >> Is it mandatory for a service to implement the multiple invocations
> >> funcionality?
> >>
> >
> >
> > well.... It *may* be that the people working on the error-handling and
> > error-codes have reserved an error code for providers who do not WANT to
> > handle multiple invocations in a single message, but I don't think so...
> >
> > I think it is mandatory at the moment.
> >
> > M
> >
> >
> >
> >
>
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