I have a JSON API that I need to provide super fast access to my data through.

The JSON API makes a simply query against the database based on the GET parameters provided.

I've already optimized my database, so please don't recommend that as an answer.

I'm using PHP-APC, which helps PHP by saving the bytecode, BUT - for a JSON API that is being called literally dozens of times per second (as indicated by my logs), I need to reduce the massive RAM consumption PHP is consuming ... as well as rewrite my JSON API in a language that execute much faster than PHP.

My code is below. As you can see, is fairly straight forward.

<?php

define(ALLOWED_HTTP_REFERER, 'example.com');

if ( stristr($_SERVER['HTTP_REFERER'], ALLOWED_HTTP_REFERER) ) {

    try {
        $conn_str = DB . ':host=' . DB_HOST . ';dbname=' . DB_NAME;
        $dbh = new PDO($conn_str, DB_USERNAME, DB_PASSWORD);
        $params = array();

        $sql = 'SELECT  homes.home_id,
                        address,
                        city,
                        state,
                        zip
                FROM homes
                WHERE homes.display_status = true
                AND homes.geolat BETWEEN :geolatLowBound AND :geolatHighBound 
                AND homes.geolng BETWEEN :geolngLowBound AND :geolngHighBound';

        $params[':geolatLowBound'] = $_GET['geolatLowBound'];
        $params[':geolatHighBound'] = $_GET['geolatHighBound'];
        $params[':geolngLowBound'] =$_GET['geolngLowBound'];
        $params[':geolngHighBound'] = $_GET['geolngHighBound'];

        if ( isset($_GET['min_price']) && isset($_GET['max_price']) ) {
                $sql = $sql . ' AND homes.price BETWEEN :min_price AND :max_price ';
                $params[':min_price'] = $_GET['min_price'];
                $params[':max_price'] = $_GET['max_price'];
        }

        if ( isset($_GET['min_beds']) && isset($_GET['max_beds']) ) {
                $sql = $sql . ' AND homes.num_of_beds BETWEEN :min_beds AND :max_beds ';
                $params['min_beds'] = $_GET['min_beds'];
                $params['max_beds'] = $_GET['max_beds'];
        }

        if ( isset($_GET['min_sqft']) && isset($_GET['max_sqft']) ) {
                $sql = $sql . ' AND homes.sqft BETWEEN :min_sqft AND :max_sqft ';
                $params['min_sqft'] = $_GET['min_sqft'];
                $params['max_sqft'] = $_GET['max_sqft'];
        }

        $stmt = $dbh->prepare($sql);

        $stmt->execute($params);
        $result_set = $stmt->fetchAll(PDO::FETCH_ASSOC);

        /* output a JSON representation of the home listing data retrieved */
        ob_start("ob_gzhandler");   // compress the output
        header('Content-type: text/javascript');
        print "{'homes' : ";

        array_walk_recursive($result_set, "cleanOutputFromXSS");
        print json_encode( $result_set );

        print '}';

        $dbh = null;
    } catch (PDOException $e) {
        die('Unable to retreive home listing information');
    }

}


function cleanOutputFromXSS(&$value) {
    $value = htmlspecialchars($value, ENT_QUOTES, 'UTF-8');
}


?>

How would I begin converting this PHP code over to C, since C is both better on memory management (since you do it yourself) and much, much faster to execute?