Re: Perfornamce Q

Jean-Christian Imbeault <jc@mega-bucks.co.jp> writes:
> But why would they be hurting me? The update is on a column that has no
> constraints on it.

Doesn't matter: any update will fire the foreign-key check trigger.

Whether this is necessary or not I dunno, but someone's thought of
it before: in the code I see
    /*
     * Note: We cannot avoid the check on UPDATE, even if old and new key
     * are the same. Otherwise, someone could DELETE the PK that consists
     * of the DEFAULT values, and if there are any references, a ON DELETE
     * SET DEFAULT action would update the references to exactly these
     * values but we wouldn't see that weired case (this is the only place
     * to see it).
     */


            regards, tom lane