I should caveat this post with the often used phrase, ‘don’t try this at home kids’. When tinkering with the guts of any system and modifying the information being sent to and from a service by ‘hacking’ into the request pipeline of a message your opening up a whole can of performance and stability worms that need a great deal of testing under load to understand the direct effect on the scalability of any site. A Simple Question This post is based upon a question I had with a customer at our recent DeveloperHub conference in Birmingham. He asked how it would be possible to watermark an image...

The other day I built a computer almost from scratch. I can admit it, I can nerd it with the best of them when pressed, ok I don’t even need to be pressed. I had a bunch of components lying around, a not too old processor, a bunch of fast RAM and a laptop hard drive all I needed was a case. That was easy to rectify as I’ve always fancied building a little PC and Shuttle do some excellent barebones machines. Now the premise of this post is not the coolness of my new computer (although it is quite nice) but the ease at which it took to build. When I was Young. When I was young and the ‘internet...

Before you read on this isn’t a post devoted to image caching. This is a post about data caching in general with image caching being an extreme form of data caching. It comes from a bit of work I did recently caching data from a tracking feed. It’s based around why you want to cache, what data you might need to cache and how you might cache (I used .NET but you can do it in all major web development languages). Caching has often been the premise of web sites that want to be, and I’m using a technical terms here, ‘screamingly fast’ and not ‘snail slow’. Caching before caching was...

There has been a long standing rule of thumb when deciding how many instances to give a map service to give optimal performance. Finding this information has sometimes been hard although surprisingly when asked for this information the other day, and failing to find it, I decided to see if it was on the new resource centre. Fortunately the is a page on services performance. http://resources.esri.com/enterprisegis/index.cfm?fa=performance.app.services Here it not only gives the ‘rule of thumb’ for the number of instances for a map service (2.5 * #CPUs) but also a whole series of information about...