Facebook: how preload FQL works?

On "Advanc开发者_如何学Goed" tab of my app settings I've seen "Preload FQL" option with description "Facebook will send the result of these FQL queries as JSON-encoded POST parameters to your Canvas URL". I set it:

{
"test": {
"pattern": ".*",
"query": "SELECT uid2 FROM friend WHERE uid1 = {*user*}"
}
}

but it doesn't post anything related into my app. I tried many ways but not successfully. Could someone point me out what did I do wrong?

I found the answer by myself: preload FQL isn't supported in the new API. Detailed here: http://github.com/facebook/php-sdk/issues/issue/175

Preload FQL Query and Multiquery.
This section applies to FBML canvas pages, but not to websites or IFrame canvas pages. http://developers.facebook.com/docs/guides/performance/

You can achieve many of the same results that you did with FQL Preloading by using Grapi API Batch Requests and FQL Multiquery. These two methods allow the same optimizations as FQL Preloading, but with a cleaner and more performant interface.

Also, the performance doc mentioned here has been removed because it contained of out-of-date information. The suggestions from that doc are now being interwoven throughout other parts of the documentation, in appropriate places.