Comment on Things that don’t work well with MySQL’s FOREIGN KEY implementationparentComments−Phelinofist3yWhat's wrong with non-integer primary keys?−tomnipotent3yYou can pack fewer of them into a page, which means more disk IO for things like index scans.−takethisdownplz3ybesides performance for using something that is not often tested by devs working in performance, bad support for locale collating and open you for bugs such as indexing on email but allowing application to store both upper and lower case etc.−evilspammer3yI would expect they're referring to UUIDs or something
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What's wrong with non-integer primary keys?
You can pack fewer of them into a page, which means more disk IO for things like index scans.
besides performance for using something that is not often tested by devs working in performance, bad support for locale collating and open you for bugs such as indexing on email but allowing application to store both upper and lower case etc.
I would expect they're referring to UUIDs or something