Avoiding the startup time for webservice xml serialization

The short version

In the build tab of a project’s properties is an option called “Generate serialization assembly”, turn it to “On” to theoretically improve performance.

The long version

Recently I’ve been working on speeding up a web application that depends heavily on a huge webservice: 884 “operations” are supportedFirebug + document.getElementsByTagName(“li”).length, the wsdl is 2 megabytes. Startup takes several minutes before anything happens. And it is mostly the startup time causing problems, things go smoothly after that.

While trying to improve things I found this single line causing most of the delay: _myStore = new WebServices3(); And it was only the first time that the webservice was initialized that the delay happened.

I started searching and ran across a knowledgebase article explaining how to create an XmlSerializers assembly. Apparently the XmlSerialization process usually generates code at runtime and this can take a while. The article explained how to pregenerate this code to save startup time later. I tried it, it didn’t seem to help all that much and it was a pain to fit into the build process.

I later found a page on MarkItUp about SGen.exe. It was a new feature in .net 2.0 that I remember hearing about. Then I found this post on kiwidude.com about how Visual Studio didn’t call sgen correctly for him.

I never noticed it before (maybe because I had to scroll down the properties page), but there was a simple drop down in Visual Studio for this. Switching it from Auto to On built the assembly automatically!

The end

Once enabled, build time became much longer and startup times were a little better. The change wasn’t as dramatic as I had hoped. I think from here I’m going to create a much smaller, specialized web service since I have access to the web service machine and we’re only using a handful of the 800 methods available.