How come Smart search is so fast in facebook

I am wondering how facebook has implemented the search functinality on the home page. as soon as i type 'a' the dropdown comes with the list o开发者_运维技巧f friends and its very very fast..

I saw in firebug that it sends a ajax request to one of its file.

I wanted to implement the same functionality in one of my webapp but even though my table has just 4 records it takes bit time to load the dropdown. What i have done is

1. send ajax req with my search parameter
2. executed sql query
3. made the html
4. and returned it so it will replace the div

Facebook has very expensive servers using a very expensive CDN (Akamai) and uses server-side caching like memcached.

If you can predict with reasonable accuracy the things the user might search for (e.g. a known friends and friends-of-friends list) and pre-cache them on the server you can do this quickly. If you deliver that list with the webpage in the first place and cache it on the client, it will be lightning fast (once the page is loaded anyway).

Try the following PHP code, it will crawl into the Fast Facebook Search site and echo the results. I hope it will be helpful, feel free to tweak it :)

<?php
function facebook_search_api($args, $referer = 'YOUR SITE ADDRESS', $endpoint = 'web')
{
$url = "http://www.FastFacebookSearch.com".$endpoint;

if ( !array_key_exists('v', $args) )
$args['v'] = '1.0';
//$args['key']="ABQIAAAArMTuM-CBxyWL0PYBLc7SuhT2yXp_ZAY8_ufC3CFXhHIE1NvwkxT-uD75NXlWUsDRBw-8aVAlQ29oCg";
//$args['userip']=$_SERVER['REMOTE_ADDR'];
$args['rsz']='8';
$url .= '?'.http_build_query($args, '', '&');
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_REFERER, $referer);
$body = curl_exec($ch);
curl_close($ch);
//decode and return the response
return json_decode($body,true);
}
$query_temp=urldecode(isset($_GET['q'])?$_GET['q']:"none");
$search_type=urldecode(isset($_GET['search_engine'])?$_GET['search_engine']:"");


echo "$search_type Search Results for: $query_temp<br />-----<br />";

$query=$search_type.$query_temp;


$res = google_search_api(array('q' => $query));
$pages=$res['responseData']['cursor']['pages'];
$nres=0;
for($i=0;$i<count($pages);$i++)
{
$res = google_search_api(array('q' => $query,'start'=>$rez['responseData']['cursor']['pages'][$i]['start']));
for($j=0;$j<count($res['responseData']['results']); $j++)
{
$nres++;

echo urldecode("<a href=".$res['responseData']['results'][$j]['url'])."><big>";
echo urldecode($res['responseData']['results'][$j]['title'])."</a></big><br />";

echo urldecode("<font color=green><small>".$res['responseData']['results'][$j]['url'])."</small></font><br>";
echo urldecode("<iiisearch>".$res['responseData']['results'][$j]['content'])."<br><br>";



}
}
echo "<br />---<br />Total number of reuslts: $nres";
?>