https://blog.wongcw.com/2020/06/22/%e6%b8%85%e7%90%86redis%e4%bd%94%e7%94%a8%e5%85%a7%e5%ad%98%ef%bc%8c%e4%b8%a6%e9%99%90%e5%88%b6maxmemory%e6%9c%80%e5%a4%a7%e4%bd%94%e7%94%a8%e5%85%a7%e5%ad%98%ef%bc%8c%e8%a8%ad%e7%bd%aeredis%e7%bd%ae/