Re: someone working to add merge?

Tom Lane wrote:
> If you don't have any better idea how to do it than a full table
> lock, you might as well not do it at all.  A "proof of concept" that
> doesn't solve the hard part of the problem is no proof :-(

But the problem here is not to break any kind of performance barrier, 
but to give people migrating from MySQL and alternative for REPLACE 
command.

> My first guess about a real implementation would involve extending
> the index AM API to offer a function "insert this key, or return the
> existing match if there already is one".

This assumes that there are indexes defined for the columns involved in 
the merge condition, which is not required anywhere.

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/