ADO.NET Data Services performance issue on SharePoint 2010

Question

I have an issue (I think) with my SharePoint 2010 ADO.NET Data Services.

I understand that using Data Services is an extra layer and as such might inhibit performance a little, but I was not expecting what I found.

I am running SharePoint 2010 in a VMWare machine on an SSD drive (Windows 2008 R2).

Currently, requesting mt lists of lists takes 0.5 seconds consistently, even though it's only a collection of 20 list names:

http://localhost:99/sites/blah/_vti_bin/ListData.svc

Using the Server Object Model, this takes 0.05 seconds. ADO.NET seems to be 10x slower Obviously the overhead might be flat and at higher volumes plateau at a 0.4 second overhead regardless. But it's still slow in my opinion.

I have done a lot of tests of serializing XML, custom WCF services etc. and nothing seems to indicate that such a small results set should take so long to load.

Any suggestions would be incredibly welcome!!

Or is this the performance I should expect??

What do other people get?

Many thanks

Answer 1

My experience has been that the Client OM (at least for JavaScript) is a bit faster than the List Data service, but the performance differences for most queries has been very close. Certainly not the kind of difference you are seeing, but I never specifically measured the $metadata operation.

Normal List Data queries against a list are just mapped to the underlying Linq provider and executed using native SharePoint CAML. In this regard, the List Data service is a relatively thin layer over native SharePoint functionality.

When you invoke the root ListData.svc to return the lists on the site, you are invoking the $metadata operation of OData, and the List Data Service has to create and format the AtomPub feed for that operation custom. There is no native SharePoint equivalent. I suspect that is what is taking the extra time.