Re: on update / on delete performance of foreign keys

In article <41F5088D.8060702@phlo.org>,
"Florian G. Pflug" <fgp@phlo.org> writes:

>> PostgreSQL doesn't automatically add indexes to foreign-key
>> columns. That sounds like the issue to me.

> Oh... *feeling a bit stupid*... Seems that I got confused, because it
> requires an index to exist on the referenced table (To speed up inserts,
> updates), but not on the referencing table...

That's not quite right.  What PostgreSQL (or any other DBMS) requires
from the referenced table is a UNIQUE constraint on the column in
question so that the referencing table points to a single row, and
UNIQUE constraints are usually implemented by indices.