Read original post at Beth Massi's Blog
LightSwitch allows you to connect to multiple data sources, relate them together, and create screens to edit the data. These data sources can be a variety of databases like SQL Server and SQL Azure, SharePoint, and custom RIA services. With the release of Visual Studio 11 Beta, the next version of LightSwitch also allows you to connect data services via OData which are often hosted remotely. When the size of the data in these data sources get too large, or the distance between them increases (i.e. Internet based data services), performance decreases. Contributing factors are the size of the data set coming down the wire is too big, the number of fields to search on in the table is high, or the size of the data in the tables has grown very large.