This is something new I also discovered in the SharePoint 2010 SDK beta.
You probably know that there is a best practice to avoid lists, or actually views or folders, with more than 2,000 items. Joel Oleson wrote a bit on this in a recent article, describing Managing Lists and Libraries with Thousands or Millions of Items. You’ll also learn some extremely valuable information about how to work with such huge lists.
Now, Microsoft are smart people, they understand that people don’t necessarily follow best practices all the time, especially end users who shouldn’t be expected to know the intricate details of how the SharePoint platform works. End users will happily throw gazillions of items into a list, happy that they finally have a place to store their info, and they shouldn’t be expected to know that this may cause performance problems.
So, for the next version of SharePoint, Microsoft has taken the bull by its horns and implemented list throttling. Basically, this allows the administrators of a SharePoint installation to set hard limits on how big lists, views, and queries should be, before an exception is thrown.
Let me quote what I wrote in the first issue of the SharePoint 2010 Beta series of USP Journal.
[…] there is a new property [of SPList] called IsThrottled that reveals some information about the performance enhancements of SharePoint 2010. In a web application, you can now set a MaxItemsPerThrottledOperation, and if the number of items in a list, as retrieved by the ItemCount property, exceeds the value from the property, the list is throttled.
The throttling works by causing SPList queries to throw an SPQueryThrottledException to avoid performance overload.
However, the SPQuery now includes a new property called RequestThrottleOverride. Basically, this property lets the SPQuery request an override of the throttling, which will allow some users, defined by the farm administrators, to bypass the exception.
So, it seems that it will be a lot easier for administrators to maintain and manage performance in a site with large lists.
By the way, you can read the first issue free at http://www.sharepoint2010beta.com/.
Found this article valuable? Want to show your appreciation? Here are some options:
a) Click on the banners anywhere on the site to visit my blog's sponsors. They are all hand-picked and are selected based on providing great products and services to the SharePoint community.
b) Donate Bitcoins! I love Bitcoins, and you can donate if you'd like by clicking the button below.
c) Spread the word! Below, you should find links to sharing this article on your favorite social media sites. I'm an attention junkie, so sharing is caring in my book!