Description:
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Hello there folks. This is my first bug report so please go easy on me, I'll try my best anyway. 

Just recently I've updated the mongo package (https://pecl.php.net/package/mongo) from version 1.5.1 to 1.6.3 and, as soon as I did it, all operations started to take longer (like 30x longer, it used to take 10ms, now it takes around 300ms). I went back to version 1.5.1 and started updating one version at a time. By doing so I figured this started to happen on version 1.5.6, up to version 1.5.5 the performance was just fine. 

Here we have a gap where I installed ver 1.5.5
https://www.dropbox.com/s/9uqo1rf6q5uwvj3/Screen%20Shot%202015-04-06%20at%204.21.42%20PM.png?dl=0

And here we have the performance on ver 1.5.6
https://www.dropbox.com/s/oqv0ty7fiqpo5if/Screen%20Shot%202015-04-06%20at%204.21.34%20PM.png?dl=0

This script has simple findOne operations.






Test script:
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I'm placing a generic findOne query on mongo, you could see the problem with any find operation, though. 

<?php

$articles = $mongo->my_db->articles;

$article = $articles->findOne(array('_id' => new MongoId('47cc67093475061e3d9536d2')));

?>

Expected result:
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I expect the operation to take about 10ms as it used to take. 

Actual result:
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The actual result can be seeing on the screenshot mentioned above.