Re: INSERT ... ON CONFLICT {UPDATE | IGNORE}

On 2014-09-29 15:16:49 -0700, Kevin Grittner wrote:
> Andres Freund <andres@2ndquadrant.com> wrote:
> 
> > Wrong. You can't realistically implement the guarantees of UPSERT
> > without a corresponding UNIQUE index.
> 
> You definitely can do it; the question is what you consider
> reasonable in terms of development effort, performance, and
> concurrency.

Right. You can exclusively lock the table and such. The point is just
that nobody wants that. I.e. people want to be warned about it.

> I think the problem can be solved with non-scary values of pretty much
> any two of those.  I guess my assumption is that we won't handle the
> general case until someone wants to put the substantial development
> effort into making the other two acceptable.

Which would be a major loss because MERGE is rather useful outside of
atomic upsert.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services