A critical vulnerability was discovered in React Server Components (Next.js). Our systems remain protected but we advise to update packages to newest version. Learn More

Per Bjurström
Apr 3, 2009
  19725
(0 votes)

Optimize startup time in ASP.NET

Microsoft published a new knowledge base article on April 1st and its not a joke:

FIX: You experience very slow performance on an initial request to an ASP.NET Web site after you change the App_Code folder, the bin folder, or the Global.asax file

I installed the fix and it seem to cut down 50% of the startup time when I recompile my project. Try it out yourself and let me know if it helps.

The magic switch is optimizeCompilations=”true”.

“When it is turned on, the compilation takes a less conservative approach. If you only change the App_Code folder, the bin folder, or the Global.asax file, only the affected files are recompiled. Previously compiled pages are not recompiled.”

   1: <>compilation defaultLanguage="c#" debug="true" optimizeCompilations="true">

The Windows Vista version can be downloaded directly from here (even though the title says its for another fix).

Apr 03, 2009

Comments

Steve Celius
Steve Celius Sep 21, 2010 10:32 AM

I guess this would also apply to EPiServer 4 projects?

I'm running XP, and so want to download and install it, but looks like I have to open a support case to get the fix.

/Steve

per
per Sep 21, 2010 10:32 AM

As long as you have a .NET 2.0 project which seems to be a requirement.

You can contact Microsoft Support and ask them to mail you the fix without opening a case, I've done that with other fixes and it has not been a problem.

Steve Celius
Steve Celius Sep 21, 2010 10:32 AM

I was unable to find this hotfix for Windows 7, and I'm not sure it is even applicable or neccessary. I added the attribute to my web.config, and my site still works. It is a relatively fresh windows install, so I can't say if the performance it better, but it can't hurt (I hope).



Sep 21, 2010 10:32 AM

I am running IIS on Windows Vista x64. I tried throwing the property into my web.config WITHOUT grabbing any hotfix to see what happens, and it worked! My load times improved tremendously. I can modify code in App_Code or dependent projects, and the load time of the website is very quick, less than one second compared to 7 seconds previously.
/ Tyler Collier

Sep 21, 2010 10:32 AM

Oops, I meant to say IIS 7.

And I forgot to say thanks to Per Bjurström for the tip!
/ Tyler Collier

per
per Sep 21, 2010 10:32 AM

Cool Tyler, I guess they included it in some update then.

Please login to comment.
Latest blogs
Building simple Opal tools for product search and content creation

Optimizely Opal tools make it easy for AI agents to call your APIs – in this post we’ll build a small ASP.NET host that exposes two of them: one fo...

Pär Wissmark | Dec 13, 2025 |

CMS Audiences - check all usage

Sometimes you want to check if an Audience from your CMS (former Visitor Group) has been used by which page(and which version of that page) Then yo...

Tuan Anh Hoang | Dec 12, 2025

Data Imports in Optimizely: Part 2 - Query data efficiently

One of the more time consuming parts of an import is looking up data to update. Naively, it is possible to use the PageCriteriaQueryService to quer...

Matt FitzGerald-Chamberlain | Dec 11, 2025 |

Beginner's Guide for Optimizely Backend Developers

Developing with Optimizely (formerly Episerver) requires more than just technical know‑how. It’s about respecting the editor’s perspective, ensurin...

MilosR | Dec 10, 2025