Dealing with Throttling restrictions in Exchange Web Services on Exchange 2010 SP1 in scripts and code
In Exchange 2010 SP1 throttling is enabled by default and while for the best part this is a good thing there are a few things you may need to be careful of if you have written code that retrieves a large number of items from a mailbox folder. While you can disable or set custom throttling polices for your application or scripts its generally a better idea to build your code to work within these throttling thresholds. With EWS the throttling policies affect a number of different areas from the number of concurrent connections one user can establish to a server, limits on the number of subscriptions and also the CPU time one particular user can consume when executing particular operations. For the most part if your using simple single threaded scripts where your not executing requests concurrently most of the settings wont have any bearing. The one policy setting that will have a direct affect on existing scripts or code is the EWSFindCountLimit which by default is limited to 1000. Thi