在我的许多应用程序中，一个非常常见的操作只是简单地检查一个持久字符串的存在，该字符串可以是唯一的用户名，文件名/ URL，UUID或UNIQUE（）id或“通用主键”。过去，我没有考虑太多，只是在MySQL中创建了一个标准表来跟踪此情况。
I recently was told that this equivalent operation of simply checking for a unique string should probably just be done on the filesystem, check file_exist() on a path.
我的问题是，什么时候应该使用MySQL而不是仅仅（？）文件系统？
我的天真理解是MySQL设计为索引更好-但这仅适用于更复杂的操作吗？
我有一些担心：
- Does PHP
file_exists()degrade when there are a large number of files in a folder? At which point should you "shard" a folder on an CentOS or Ubuntu Apache server (actually, I am not sure how dependent on PHP version, OS, web server version this is)? - If one needs to do things like list files, does that also come at a high performance cost over just your typical MySQL
SELECT Like '%bla%'for example?
引理：两个系统是否应该并行创建？用于快速检查的文件系统和用于列表/搜索/其他操作的MySQL系统？
