[OpenLayers-Users] Updating Data: Comet, Push, or What?

[Michael]

Thanks Arnie

You may be right, and certainly ARE right about sailboats being slow.  
Actually, I don't care about latency much at all.  In fact, we will 
delay/obfuscate the data by as much as four hours anyway in order to 
reduce tactical use by competitors.  It's really the issue of an AJAX 
request staying open on a conventional server apparently ties up resources.

Your suggestion of simply sticking with conventional polling, but 
reducing the cycle count, is an excellent one, and a heckuva lot easier 
to implement.

I had stumbled across websockets at the same link you provided just a 
moment ago.  I guess the issue there is it is not fully implemented or 
deployed, but WILL BE.

I'M STILL interested in other views on this.  With 90k visitors a day, 
reducing server load while delivering an exciting experience is a good 
thing.

Michael




On 5/20/2011 7:52 AM, Arnie Shore wrote:
> I'll certainly defer to others who've done measurements here, but from 
> some experience with our open source computer-aided-dispatch application:
>
> WRT " ... It seems that the "long polling" method or, worse, looped 
> queries, can lead to server overload ... ."  I expect here that the 
> culprit is in implementers trying to minimize latency by using an 
> excessively short cycle period, which results in hammering the server.
>
> Riding to rescue is WebSockets - 
> http://en.wikipedia.org/wiki/WebSockets -  which supports server push, 
> and for which many of us wait in eager anticipation.  It's a nice 
> solution to the general problem of http in a real-time environment.
>
> At this writing, the protocol spec is fairly far along but 
> implementation is uneven.  I'll guess that it might be widely 
> available in the latest browsers later this year.
>
> Pending that availability, consider conventional solutions like those 
> you've named, but with a reasonable cycle time.  And live with the 
> latency.  (AS fast as these boats are, they remain sailboats!)
>
> AS
>
>
> On 5/20/2011 10:14 AM, Michael wrote:
> > Greetings Mappers!
> >
> > I've built a trans-pacific charting application intended to be used for
> > near real-time sailboat tracking.
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