Currently I am storing my session data in a MEMORY table. I noticed though as records get deleted (due to inactivity), overhead is generated. Unfortunately, MEMORY does not offer a OPTIMIZE command, nor can memory really be "optimized" anyways. So, from anyone who has ever done this, what is the best way to go? InnoDB or Memory for this type of situation? If you went with memory, what is the deal with the overhead, and what ways did you use to combat it?