Re: Concurrent MERGE

On Thu, Aug 5, 2010 at 11:43 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
> Looks like MERGE is progressing well.
>
> At 2010 Dev Mtg, we put me down to work on making merge work
> concurrently. That was garbled slightly and had me down as working on
> predicate locking which is the general solution to the problem.
>
> Do we still need me to work on concurrent MERGE, or is that included in
> the current MERGE patch (can't see it), or is that covered elsewhere
> (for example Kevin Grittner's recent work)?
>
> Still happy to do work as proposed, just checking still required.

I suspect Kevin's patch will solve it if using a sufficiently high
transaction isolation level, but something else might be needed
otherwise.  However, I confess to ignorance as to the underlying
issues?  Why is MERGE worse in this regard than, say, UPDATE?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company