Facebook API batch request is very slow - facebook

Question

I'm writing a web app that allows users to search data from their Facebook profile as well as that of their friends (who've also authorized the app). Initially I was looping through the friends and making separate API calls to get the friend data, but that was SUPER slow. So I switched to building an array of API requests and submitting one batch request.
The batch request is supposed to be the solution to my problem, but it's STILL agonizingly slow. My page loads are around 15 seconds and I cannot figure out why. The documentation claims that each request in the batch is processed in parallel, but it sure doesn't seem that way. Is it relevant that each of my batched requests takes an unique access token? The documentation doesn't indicate that this is a problem, but the documentation doesn't say a lot of things...
Here's an example of one of my batch queries:
[
{"method":"GET",
"relative_url":"\/#####\/friends?fields=name,first_name,last_name,id,work,education&access_token=#####"},
{"method":"GET",
"relative_url":"\/#####\/friends?fields=name,first_name,last_name,id,work,education&access_token=#####"},
{"method":"GET",
"relative_url":"\/#####\/friends?fields=name,first_name,last_name,id,work,education&access_token=#####"}
]
Just to give you some context, the app makes one API request to get the user's friends. Then it loops through those results and builds a batch request for each friend (that has authorized the app) and sends a second API batch request using the PHP SDK ($json_batch is a batch request like the one shown above):
$rawdata = $facebook->api('?batch='.$json_batch, 'POST');
(exemplified above). The cumulative results are checked for matches against the user's search query and echoed back to the user. Any ideas why this should take 20 seconds to happen??
UPDATE:
I added some code to track the time at various times during the execution of the script...
The entire class runs in 11-13 seconds. The first FB api call (to the graph) takes 0.6 seconds. The second batch call is 10-11 seconds! But WHY?

Answer 1

I'm not sure why the batch requests take that long, but to answer the access token per request, no it's necessarily to do so, unless you put different tokens, if you are using the same token then you can simply (as in the documentation):
curl \
-F 'access_token=…' \
-F 'batch=[ \
{"method": "GET", "relative_url": "me"}, \
{"method": "GET", "relative_url": "me/friends?limit=50"} \
]'\
https://graph.facebook.com
You can however get the same exact information using a single FQL query:
SELECT uid, username, name, first_name, middle_name, last_name, work, education
FROM user
WHERE uid IN (SELECT uid2 FROM friend WHERE uid1 = me())
This also removes the need to query separably for the friends of the logged in user first, but if you do have a list of friend ids you can put those in the IN clause instead of the inner query.
Maybe this fql solution will return faster.