There are some use cases in which tailable cursors over a non capped collection may be useful. This is a mitigation of the inability to shard (and therefor sale) capped collections (Tickets already open).

The desired behaviour would be:
A tailable cursor open over a collection would send the data as any change on the collection happens (for inserts, deletes and updates). In other words would be something like make the op-log cluster wide visible. The order should be only strict per shard.

An example use case would be a message queue, avoiding polling the table with constant queries. Another example would be a distributed probe system, were the measurements are sent to a DB and processed by multiple readers.

If there's already a wait to achieve this behaviour in a sharded environment, let me know.

Thanks in advance.