[mapserver-users] Controling the amount of concurrent GetMap requests
List, Does anybody know how to control number of concurrent GetMap requests in MapServer? Thanks, Asad ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Controling the amount of concurrent GetMap requests
On 5/26/2011 12:52 PM, Asad Ullah wrote: List, Does anybody know how to control number of concurrent GetMap requests in MapServer? You can't do this within mapserver because each instance of mapserver is not aware that there are any other instances running. Presumably, you would have to look at Apache or IIS and see what controls there are to limit concurrent requests to a URL or something like that. I more basic question in my mind is what do you want to happen if this limit is exceeded. What would you expect the user experience would be if you were to make a limit+1 request? would it get rejected, queued up until another request finished? Anyway probably not a mapserver question other than to say mapserver does not do this. -Steve W ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Controling the amount of concurrent GetMap requests
I would think that the thinking here is that a server only scales well to some number of concurrent requests. That beyond that number, all requests suffer. In this case it's better to queue the requests rather than try to process them, meaning queuing improves performance overall. On Thu, May 26, 2011 at 1:57 PM, Stephen Woodbridge wood...@swoodbridge.com wrote: On 5/26/2011 12:52 PM, Asad Ullah wrote: List, Does anybody know how to control number of concurrent GetMap requests in MapServer? You can't do this within mapserver because each instance of mapserver is not aware that there are any other instances running. Presumably, you would have to look at Apache or IIS and see what controls there are to limit concurrent requests to a URL or something like that. I more basic question in my mind is what do you want to happen if this limit is exceeded. What would you expect the user experience would be if you were to make a limit+1 request? would it get rejected, queued up until another request finished? Anyway probably not a mapserver question other than to say mapserver does not do this. -Steve W ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Controling the amount of concurrent GetMap requests
On 11-05-26 05:01 PM, Mark Korver wrote: I would think that the thinking here is that a server only scales well to some number of concurrent requests. That beyond that number, all requests suffer. In this case it's better to queue the requests rather than try to process them, meaning queuing improves performance overall. Folks, I will just note that Apache + FastCGI makes it pretty easy to limit the number of concurrent requests being processed and when saturated the new requests are queued. I presume they would timeout after a while if there is just too much traffic. Best regards, -- ---+-- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush| Geospatial Programmer for Rent ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] Controling the amount of concurrent GetMap requests
On 5/26/2011 5:07 PM, Frank Warmerdam wrote: On 11-05-26 05:01 PM, Mark Korver wrote: I would think that the thinking here is that a server only scales well to some number of concurrent requests. That beyond that number, all requests suffer. In this case it's better to queue the requests rather than try to process them, meaning queuing improves performance overall. Folks, I will just note that Apache + FastCGI makes it pretty easy to limit the number of concurrent requests being processed and when saturated the new requests are queued. I presume they would timeout after a while if there is just too much traffic. Best regards, Mark, Yes, this is what I was trying to say. And to expand on this, to make scalable systems, there is normally some layering of services. So while mapserver know how to render maps, Apache is what receives requests, queues them, knows how many requests are running, so this is the logical place to deal with this, not in mapserver. You can also place a load balancer in front of a farm of servers and have it route requests to the least loaded system. But this even starts to fail at some point, then you need to look at other solutions like caching tiles. In my 11+ years of working with mapserver, I can say that often mapserver is disk I/O bound, and that you can do stuff to speed that up which makes in CPU bound. It is best to test your setup to find where the bottlenecks are and then work on eliminating the top ones, then retesting to see how the bottlenecks have shifted. This optimizes a single mapserver, then you need to look at how to scale that maybe across multiple servers depending on your load and usage requirements. -Steve W ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
