I / O性能完整性检查 - 检查文件是否存在

Are you aware of any serious performance problems with checking if a file exists before you open it and send it? The context for this is a web application that serves up files dynamically via an ASP page. I was told that there is no check for whether or not the file exists because the database stores this information and shouldn't be wrong. It is of course sometimes wrong for any number of reasons so we end up sending back nothing leaving the user unhappy.Are you aware of any serious performance proble