Performance Impact of High Item Counts and Restricted Views

This is a great article - during my days as a CPR engineer I spent many an hour understanding the impact of this and how it effected Performance on an Exchange server.

It is very useful and will give you a better understanding of what an Exchange server has to do when creating a view in a folder. It also highlights what restricted views are and how they are generated and used.

So if you are having perf issues on an Exchange server take a look at this doc and check item counts. Even if the this is not the cause it is a great read to understand some of the complexities of ESE B+ trees