Reminds me of a problem I ran into once where someone had wanted unique but short codes as identifiers for relatively small counts, and picked a substring of a UUID:
> However, the overall takeaway was: Don’t use the MongoDB Increment value as a Unique Identifier.
However, the overall takeaway should be, as always: don't use MongoDB. Period. Every time I learn something new about it I'm baffled about why people continue to use it.
http://mattmitchell.com.au/birthday-problems-friendly-identi...