MongoDB find and remove - the fastest way

Question

I have a quick question, what is the fast way to grab and delete an object from a mongo collection. Here is the code, I have currently:

$cursor = $coll->find()->sort(array('created' => 1))->limit(1);
$obj = $cursor->getNext();
$coll->remove(array('name' => $obj['name']));

as you can see above it grabs one document from the database and deletes it (so it isn't processed again). However fast this may be, I need it to perform faster. The challenge is that we have multiple processes doing this and processing what they have found BUT sometimes two or more of the processes grab the same document therefore making duplicates. Basically I need to make it so a document can only be grabbed once. So any ideas would be much appreciated.

Answer 1

Peter, It's hard to say what the best solution is here without understanding all the context - but one approach which you could use is findAndModify. This will query for a single document and return it, and also apply an update to it.

You could use this to find a document to process and simultaneously modify a "status" field to mark it as being processed, so that other workers can recognize it as such and ignore it.

There is an example here that may be useful: http://docs.mongodb.org/manual/reference/command/findAndModify/