Query a specific list template with a web application scope

I know that is is possible to query a specific site collection using the SPSiteDataQuery but I would like to perform the same operation within a whole web application. In fact, I would like to query a开发者_开发知识库 specific list template in a whole web application.

I could loop over the site collections of the web application but it is really too much time consuming.

Does anybody have an idea ?

You might like to try doing it via a search solution instead? This depends on whether you have a content type or other property to search on, but it will scope to web applications much better.