Codeigniter Memcached会话存储未命中率很高

Question

I use Memcached service for session storage on Codeigniter based project.

As I see on every refresh cache stats updates:

**GET:**

 - Hits: +1
 - Miss: +1


**SET:**

 - Total: +2


**DELETE:**

 - Hits: +1
 - Miss: +0

Screenshot of server status :

Does anyone faced same with Codeigniter? If yes why on every refresh I have high miss rate.

Also as I see some record is added and removed from cache on every refresh.

Is this CI stuff? or maybe I missed something?

Answer 1

Finally found what's going on: Looks like these mysterious set and delete are session locks.

When I have session stored with SOME_KEY while CI updates value of this key, it creates temporary record with SOME_KEY:lock index, which is alive while write process is active.

So this is why I have high miss and set/delete rate on every refresh.