By default, Spry caches any XML data that a data set loaded on the client. If a data set attempts to load the XML data for a given URL that is already in the cache, Spry returns a reference to the cached data to the data set. If multiple data sets attempt to load the same URL at the same time, all load requests are combined into a single HTTP request to save bandwidth.

Use of data caching and of combining requests can greatly improve performance, especially when multiple data sets refer to the same XML data; at times you might need to load the data directly from the server (for example, if you have a URL that might return different data each time someone accesses it).

var dsPhotos = new  Spry.Data.XMLDataSet("/photos.php?galleryid=2000", "/gallery/photos/photo", {useCache: false })