Description:
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In fact I'm using PHP 5.3.3

persistent connections to mongodb doesn't seem to be stable enough. 

after few days, I encounter exception as "couldn't send query" and nothing works with mongodb. the serious problem is,  the connect doesn't seems to be able to fix or reconnect by itself.

After I change the persist connect key. or switch to non-persist connection, everything works.

maybe lack of automatic reconnection once break?
or meybe there can be too many opened persist connection to mongodb and exceed the limit



Reproduce code:
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$m = new Mongo("mongodb:///tmp/mongodb-27017.sock", array("persist" => "anykey")); 

// anything operate data



Expected result:
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 PHP Fatal error:  Uncaught exception 'MongoCursorException' with message 'couldn't send query.' in /data/www/2006/counter/jsc.php:39
Stack trace:
#0 /data/www/2006/counter/jsc.php(39): MongoCollection->findOne(Array, Array)