Mongodb 在我的使用情境下都拿來存統計的資料，但為避免儲存空間不足造成網站掛掉，所以定時的去檢查每個資料庫使大小是一定要的。
Mongodb is used to store statistical data in my use situation, but in order to avoid insufficient storage space and cause the website to hang up, it is necessary to check the size of each database regularly.