on line 114 of req.lua

   111     if commit then
112         rec_cdata.excess = excess
113         rec_cdata.last = now
114         dict:set(key, ffi_str(rec_cdata, rec_size))
115     end

I think it will save mem if you set a expire time on the key, like below
dict:set(key, ffi_str(rec_cdata, rec_size),60)

same advise on con.lua ,but you need to change add to set

also ,I can't figure out the uncommit mechanism in req.lua ,where and when should I call uncommit?