TileLayer causing very slow response on IIS 7.5

Dec 16, 2011 at 4:36 AM

We have created an Oil wells application with SharpMap and obviously BruTile using ASp.Net 4.0 version. It is a local web version means the shape files, web Application and everything resides on the local webserver and accessed from a browser from the same machine as usual.The number of layers were 2 i.e Bing Tiles and Countries.

 The application ran pretty well on IE 7 and IE8 with IIS 6.0.The response was always with in 3 seconds. When the app was deployed on IIS 7.5, windows 7- 64 bit edition  and IE9 the application response was too slow around 35 seconds.

 When I debugged into the Brutilelibrary(thanks for RedGate-.Net Reflector) I see the probelm was in the Render function of TileLayer class. In this class I saw a ThreadPool was used with a WaitCallBack and AutoResetEvent which was just making the Bitmpaps from the tiles and storing in a collection. When I disabled the bing layer the application just ran in less than 2 sec. The VectorLayer class render was fast for the countries layer.

Is there any problem with the usage of ThreadPool class on IIS 7.5(Is IIS starving and making the response slow when you a use Threadpool in the application).

Kindly look into the problem and respond .




Dec 16, 2011 at 10:13 AM

Hello Hemakumar,

I have not heard of any problems with a specific IIS version. There has been a problem with proxy settings. Since these could be different on your IIS 7.5 server this might be the problem here. You could try to download the BruTile source and build it with your version of SharpMap to see if this makes a difference. 

see issue here:



Dec 20, 2011 at 7:10 AM

Hello Paul,

Thanks alot. Now it is running under 2 seconds after we compiled with the patch specified by you.