Re: Why does Postgres allow duplicate (FK) constraints

Alban Hertroys, 26.03.2013 17:17:
> It can make sense during a maintenance window, if you create a new
> (redundant) FK constraint concurrently to replace the existing one.
> If you'd first remove the existing constraint, you're allowing FK
> violations until the new constraint has finished creating its index.
>
> This happens for example if you want to use a different index
> algorithm, say a gist index instead of a btree index, or if the
> initial index has gotten corrupt somehow and it needs reindexing.

I can understand this for indexes, but a foreign key constraint does not create one.

Regards
Thomas