Re: MERGE Specification

On Thursday 24 April 2008 23:40, Tom Lane wrote:
> Robert Treat <xzilla@users.sourceforge.net> writes:
> > Perhaps a better option would be to implement Merge per spec, and then
> > implement a "replace into" command for the oltp scenario.  This way you
> > keep the spec behavior for the spec syntax, and have a clearly non-spec
> > command for non-spec behavior.
>
> In that case, it's a fair question to ask just who will use the "spec"
> syntax.  As far as I can tell from years of watching the mailing lists,
> there is plenty of demand for a concurrent-safe insert-or-update
> behavior, and *exactly zero* demand for the other.  I challenge you to
> find even one request for the "spec" behavior in the mailing list
> archives.  (Simon doesn't count.)
>

AIUI the current implementation is designed to avoid race conditions partially 
at the cost of being insert friendly and somewhat update unfriendly. My guess 
is that most of the people wanting this for OLTP use want an update friendly 
implementation (that's certainly been the majority of cases I've needed 
myself, and that I have seen others use). 

-- 
Robert Treat
Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL