Messaging Queues ‣ Blog ‣ Content Management ‣ Anything you want *Capped collections behave as fixed-sized FIFO queues *TTL collections have a special index that will automatically remove old data
acknowledge the write, including the primary The timeout for the write, without it the write could block forever http://docs.mongodb.org/manual/core/write-operations/#write-concern
: <num (documents matching query)>, 'nscanned': <num (documents scanned)>, 'scanAndOrder': <boolean>, } http://docs.mongodb.org/manual/reference/explain/ You want n and nscanned to be as close together as possible If scanAndOrder is True, the index can’t be used for sorting