Re: DWR Scalabilty And Early Closing Mode

by r123 :: Rate this Message:

That is good to hear. This may be a dumb question, but in your opinion, what would be the main benefit of using DWR? I've been to the website, but would like to hear your thoughts. We are currently having to justify using DWR. What would it give us as opposed to just writing your own ajax functions. We are in the process of doing a POC using DWR with TIBCO GI for a project. I find it helps alot when we can actually access the java object from the client and then add that object to the GI matrix. It saves us from having to create our own CDF mapping. As it turns out ease of use cannot be the deciding factor (crazy I know). Just wanted to get your thoughts on why would I use DWR?

Thanks
r123

Joe Walker-3 wrote:

DWR will work just fine in the same page as either. There might be issues
with the 2 connection limit, but you could configure DWR to use polling if
that is an issue. I expect that BlazeDS's connections won't contribute to
the 2 connection limit anyway. Also all browsers are upping their limits -
it looks like we'll all be taking about the 6 connection limit soon, which
is a much smaller problem.

There are a number of different aspects to scalability. Lightstreamer is
excellent at scaling to high data-rates, I'm not sure how it copes with
scaling to a large number of connected clients though, which is a different
matter. Note: I'm not saying that it's bad, just that I don't know how it
copes. My advice would be that DWR is easy to implement, so you might be
best off taking the easy route, and considering others if it can't grow to
meet your needs.

Joe.

On Sun, Apr 6, 2008 at 3:07 AM, r123 <ronberna@hotmail.com> wrote:

>
> I guess have the ability to sit in the same page and function. What I am
> trying to determine is if at some point we decide to use a LightStreamer
> or
> Blaze DS server, would we have to remove DWR completely. Right now we are
> using DWR to access Java objects on the client. We are trying to
> determine
> whether or not to use DWR in polling or comet mode. A concern is the
> scalabilty. If we need to have a true push application with thousands of
> clients, then a dedicated server like LightStreamer or Blaze DS may be
> needed (i'm guessing).
>
>
>
> Joe Walker-3 wrote:
> >
> > I think it depends on what you mean by "working with". Are you asking
> for
> > DWR to use them as a network transport, or to be able to sit in the same
> > page and still function.
> >
> > Joe.
> >
> > On Thu, Apr 3, 2008 at 9:59 PM, r123 <ronberna@hotmail.com> wrote:
> >
> >>
> >> So does this issue prevent DWR from currently working at all with
> >> Lightstreamer or Blaze DS?
> >>
> >> Thanks
> >> Ron
> >>
> >> Joe Walker-3 wrote:
> >> >
> >> > Lightstreamer does a lot of stuff that DWR does not currently do, so
> I
> >> > fully
> >> > expect that it will scale better. There is an issue to get DWR to
> use
> >> > lightstreamer as a conduit: http://getahead.org/bugs/browse/DWR-49,
> >> > however
> >> > this is very low priority.
> >> >
> >> > Joe
> >> >
> >> > On Wed, Mar 19, 2008 at 4:00 AM, r123 <ronberna@hotmail.com> wrote:
> >> >
> >> >>
> >> >> So would DWR in Full Streaming or Early Closing mode running on
> >> Websphere
> >> >> be
> >> >> able to handle the 10,000 concurrent users that LightStreamer
> >> advertises
> >> >> that it can handle? Also, is it possible to integrate DWR with
> >> >> LightStreamer or Flex Blaze DS servers?
> >> >>
> >> >>
> >> >>
> >> >> Joe Walker-3 wrote:
> >> >> >
> >> >> > DWR does a lot to protect the server against overloading. In the
> >> case
> >> >> of
> >> >> > Websphere, there is no custom plugin for their async servlet, so
> we
> >> >> fall
> >> >> > back to the servlet-api implementation which backs off connection
> >> >> numbers
> >> >> > to
> >> >> > prevent overloading things.
> >> >> >
> >> >> > Early closing mode is there to prevent buggy proxies messing with
> >> the
> >> >> > responses - it's not about reducing load.
> >> >> >
> >> >> > What kind of latencies are important to you? If you're ok with
> >> >> latencies
> >> >> > of
> >> >> >> 60 seconds, then you can configure DWR to poll, which should
> reduce
> >> >> the
> >> >> > server load.
> >> >> >
> >> >> > Joe.
> >> >> >
> >> >> > On Sun, Mar 16, 2008 at 4:30 PM, r123 <ronberna@hotmail.com>
> wrote:
> >> >> >
> >> >> >>
> >> >> >> We have a project that will run on a Websphere 6.1 server that
> >> needs
> >> >> to
> >> >> >> send
> >> >> >> data to the web client in real or near real time. The data will
> be
> >> >> read
> >> >> >> from a JMS topic. We are considering using DWR "Reverse AJAX" to
> >> help
> >> >> >> push
> >> >> >> this data from the web server to the web client. There are some
> >> >> concerns
> >> >> >> about how this would scale as well as failover. There is also a
> >> >> concern
> >> >> >> about the "push" vs. "pull" concept.
> >> >> >>
> >> >> >> I read some about Early Closing Mode in DWR. If I understood
> this
> >> >> >> correctly, DWR will close the http connection after 60 seconds if
> >> >> there
> >> >> >> is
> >> >> >> no activity. A question I have is does it release the socket or
> >> >> thread
> >> >> >> once
> >> >> >> that connection is closed? Would this approach be able to scale
> >> to
> >> >> >> thousands of clients or would a dedicated server component like
> >> Tibco
> >> >> >> "Ajax
> >> >> >> Messaging Service" which uses LightStreamer be needed in order to
> >> >> handle
> >> >> >> large numbers of clients? The disadvantage I read about Early
> >> Closing
> >> >> >> Mode
> >> >> >> is that many clients may possibly try to re-connect at the same
> >> time.
> >> >> >> How
> >> >> >> big of an issue is this?
> >> >> >>
> >> >> >> Any ideas on this would be greatly appreciated.
> >> >> >>
> >> >> >> Thanks
> >> >> >> r123
> >> >> >> --
> >> >> >> View this message in context:
> >> >> >>
> >> >>
> >>
> http://www.nabble.com/DWR-Scalabilty-And-Early-Closing-Mode-tp16080860p16080860.html
> >> >> >> Sent from the DWR - Users mailing list archive at Nabble.com.
> >> >> >>
> >> >> >>
> >> >> >>
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> >> >> >>
> >> >> >>
> >> >> >
> >> >> >
> >> >>
> >> >> --
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> http://www.nabble.com/DWR-Scalabilty-And-Early-Closing-Mode-tp16080860p16136629.html
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> >> >>
> >> >>
> >> >>
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> >> >>
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> >> >
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> >>
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>
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