Two identical registrations

[Lazky]

Today a user registered at our forum and somehow it ended up with two identical usernames/emailadresses, both made at the same time by this user. The user ID's are different though.
- Allow Multiple Registrations Per User = no
- Require Unique Email Addresses = yes
Angel5 (1)
Angel5 (2)

We have just updated from 4.2.1 to 4.2.2 . I hope this is not related to that and it's just an incident

[Wayne Luke]

Looks like a race condition. They registered and hit the submit button twice. Both were inserted in a period after the check for duplicates as made. While the username is indexed, a unique index is not enforced. There are no database indexes on the email address. If you get down to it, you'll find the creation date for the records is probably the same or off by mere milliseconds.

Upgrading to 4.2.2 is not the cause of this issue.