> >> Is it possible that 1060 and 1092 have the same usesysid
> in pg_shadow?
>
> > Hmmm. That was the problem. Thanks! By the way, could you
> please define a
> > unique constraint on column 'usesysid' in future in PostgreSQL?
>
> Yup, there should be one (and one on usename, too). Not sure why it's
> been overlooked so far.
The usesysid was originally intended to map pg users to unix accounts.
I do not see why it should not be possible to map different pg users
to a single unix account. The above imho stems from an improper use of this
column which needs to be fixed, not the column made unique.
Andreas