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

Peter Geoghegan <pg@heroku.com>

From: Peter Geoghegan <pg@heroku.com>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>, Craig Ringer <craig@2ndquadrant.com>
Date: 2014-09-28T20:31:46Z
Lists: pgsql-hackers
On Sun, Sep 28, 2014 at 1:17 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
> MERGE INTO tab USING VALUES ('foo')
> WHEN NOT MATCHED THEN
>  INSERT (colB)
> WHEN MATCHED THEN
>  UPDATE SET colB = NEW.p1
>
> and throwing "ERROR: full syntax for MERGE not implemented yet" if
> people stretch too far.

That isn't the MERGE syntax either. Where is the join?

I've extensively discussed why I think we should avoid calling
something upsert-like MERGE, as you know:
http://www.postgresql.org/message-id/flat/CAM3SWZRP0c3g6+aJ=YYDGYAcTZg0xA8-1_FCVo5Xm7hrEL34kw@mail.gmail.com#CAM3SWZRP0c3g6+aJ=YYDGYAcTZg0xA8-1_FCVo5Xm7hrEL34kw@mail.gmail.com

We *should* have a MERGE feature, but one that serves the actual MERGE
use-case well. That is an important use-case; it just isn't the one
I'm interested in right now.

FWIW, I agree that it wouldn't be much work to do this - what you
present here really is just a different syntax for what I have here
(which isn't MERGE). I think it would be counter-productive to pursue
this, though. Also, what about limiting the unique indexes under
consideration?

There was informal meeting of this at the dev meeting a in 2012.

-- 
Peter Geoghegan


Commits

  1. Change the way we mark tuples as frozen.

  2. Add documentation for data-modifying statements in WITH clauses.