SharePoint 2010 Help

The Content Query Web Part is very useful for content aggregation and roll-up across the site collection scope. It was around in the previous version of SharePoint but has been improved in 2010 as can be seen in this MSDN Blog. There are, however, some inconveniences associated with it. CQWP may have issues with anonymous access as described here. The other issue which was discussed in this thread and also mentioned (2007) in this post is related to caching.
So, you configure a CQWP and apply some filtering. You test the results and they look OK. Then, you discover that new additions or updates are not reflected instantly – not even with a forced refresh, unless you try several times. You may go back to edit the web part and find that results are reflected immediately after an edit, but that’s not a solution.
The problem is related to caching which cannot be adjusted from the user interface. There are two workarounds: either export the web part and add a property to the exported file and re-import it (as explained in the thread above) or edit the page hosting the CQWP in SharePoint Designer to add a property to the tag directly: edit the page and while the CQWP is selected, switch to code view and add
UseCache=”False”
to the