Change Keys and Shapes

In Chapter 2, we indicated that including the change key increases performance. We could leave it at that and have everyone scratching their heads in wonder. Instead, we will tell you why and leave you scratching your head in wonder.

When Exchange Web Services receives a folder or item id that it needs to open, an interesting situation arises. Exchange Web Services knows the response shape that the caller has requested (for example, IdOnly, Default) along with the additional properties and so on, but that final list of properties is a function of the type of item or folder to which Exchange Web Services is binding. If a request comes in without a change key, Exchange Web Services blindly opens the item and determines the ...

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