Can auto transfer data from memcached to mysql DB?
Memcached is not a persistent store, so if you need your data to be durable at all then you will need to store them in a persistent store immediately.
So you need to put them somewhere - possibly a MySQL table - as soon as the data arrive, and make sure they are fsync'd to disc. Storing them in memcached as well only speeds up access, so it is a nice to have.
Memcached can discard any objects at any time for any reason, not just when they expire.
I'm building a real-time service so my real-time database need to storage in memcached before fetch to DB (Avoid to read/write mysql db too much). I want to fetch data to mysql DB when some events occur , etc : before data expire or have least-recently-used (LRU) data. What is solution for my problem ? My system used memcached , mysql ,django and python-memcache 
Thank