不合理的超时设置，最大情况就是拖爆你的服务端
SetTimeout方法是不可靠的，解释如下：
Sadly, it is a best effort timeout, its not being checked on all places. Specifically, if you send a query that ends up being rewritten into many terms (fuzzy, or wildcard), that part (the rewrite part) does not check for a timeout.SetTimeout 不是你想象的那样，没有屁用。