Currently all the stats are saved in backend-redis. If a customer is running out of memory in the redis db it would be good to be able to set a cunfigurable expiration for stats keys. 

Currently the only option is to delete the stats manually but it can be dangerous since deleting the wrong data limits will be cleared out and will affect the authorisation of the requests. Deleting Redis data requires a good understanding of how 3scale stores the keys and what you can delete. 

 
The request is to add a feature (TTL) to automate the deletion of the stats.

 Please see the THREESCALE-6571 description for important information on this topic.