Re: BUG #17892: Bug primary key

PG Bug reporting form <noreply@postgresql.org> writes:
> We have a database with over 3 milions apps in it
> Something happend we just found duplicates with same id, but we have
> constraints : PRIMARY KEY on id

With no details it's impossible to do more than speculate.
However, if these are string-type columns then a possible cause
is an OS update having changed collation rules underneath you.
There's more details about that in

https://wiki.postgresql.org/wiki/Locale_data_changes

In any case the path to follow is to manually fix the duplicates
and REINDEX.

            regards, tom lane