Re: foreign key locks

On Wed, Oct 31, 2012 at 05:22:10PM -0300, Alvaro Herrera wrote:
> Simon Riggs wrote:
> > On 31 October 2012 19:35, Noah Misch <noah(at)leadboat(dot)com> wrote:
> > > +1. I had not considered this angle during previous reviews, but I agree with
> > > Andres's position. Since this patch does not strengthen the strongest tuple
> > > lock relative to its PostgreSQL 9.2 counterpart, that lock type should
> > > continue to use the syntax "FOR UPDATE". It will come to mean "the lock type
> > > sufficient for all possible UPDATEs of the row".
>
> Yeah, I agree with this too.
>
> > So we have syntax
> >
> > FOR NON KEY UPDATE
> > FOR KEY UPDATE
> >
> > KEY is the default, so FOR UPDATE is a synonym of FOR KEY UPDATE
>
> Not really sure about the proposed syntax, but yes clearly we need some
> other syntax to mean "FOR NON KEY UPDATE". I would rather keep FOR
> UPDATE to mean what I currently call FOR KEY UPDATE. More proposals for
> the other (weaker) lock level welcome (but if you love FOR NON KEY
> UPDATE, please chime in too)

Agree on having "FOR UPDATE" without any "FOR KEY UPDATE" synonym. For the
weaker lock, I mildly preferred the proposal of "FOR NO KEY UPDATE". NON KEY
captures the idea better in English, but NO is close enough and already part
of the SQL lexicon.