I have been very excited about MongoDb and have been testing it lately. I had a table called posts in MySQL with about 20 million records indexed only on a field called 'id'.

I wanted to compare speed with MongoDB and I ran a test which would get and print 15 records randomly from our huge databases. I ran the query about 1,000 times each for mysql and MongoDB and I am suprised that I do not notice a lot of difference in speed. Maybe MongoDB is 1.1 times faster. That's very disappointing. Is there something I am doing wrong? I know that my tests are not perfect but is MySQL on par with MongoDb when it comes to read intensive chores.

Note:

• I have dual core + ( 2 threads ) i7 cpu and 4GB ram
• I have 20 partitions on MySQL each of 1 million records

Sample Code Used For Testing MongoDB

<?php
function microtime_float()
{
    list($usec, $sec) = explode(" ", microtime());
    return ((float)$usec + (float)$sec);
}
$time_taken = 0;
$tries = 100;
// connect
$time_start = microtime_float();

for($i=1;$i<=$tries;$i++)
{
    $m = new Mongo();
    $db = $m->swalif;
    $cursor = $db->posts->find(array('id' => array('$in' => get_15_random_numbers())));
    foreach ($cursor as $obj)
    {
        //echo $obj["thread_title"] . "<br><Br>";
    }
}

$time_end = microtime_float();
$time_taken = $time_taken + ($time_end - $time_start);
echo $time_taken;

function get_15_random_numbers()
{
    $numbers = array();
    for($i=1;$i<=15;$i++)
    {
        $numbers[] = mt_rand(1, 20000000) ;

    }
    return $numbers;
}

?>

Sample Code For Testing MySQL

<?php
function microtime_float()
{
    list($usec, $sec) = explode(" ", microtime());
    return ((float)$usec + (float)$sec);
}
$BASE_PATH = "../src/";
include_once($BASE_PATH  . "classes/forumdb.php");

$time_taken = 0;
$tries = 100;
$time_start = microtime_float();
for($i=1;$i<=$tries;$i++)
{
    $db = new AQLDatabase();
    $sql = "select * from posts_really_big where id in (".implode(',',get_15_random_numbers()).")";
    $result = $db->executeSQL($sql);
    while ($row = mysql_fetch_array($result) )
    {
        //echo $row["thread_title"] . "<br><Br>";
    }
}
$time_end = microtime_float();
$time_taken = $time_taken + ($time_end - $time_start);
echo $time_taken;

function get_15_random_numbers()
{
    $numbers = array();
    for($i=1;$i<=15;$i++)
    {
        $numbers[] = mt_rand(1, 20000000);

    }
    return $numbers;
}
?>