Re: ask for review of MERGE

> So the trick for MERGE on equality would be to refactor the btree api
> so that you could find the matching leaf page and *keep* that page
> locked. Then do an update against the conflicting row found there if
> any without ever releasing that page lock. Someone else can come along
> and delete the row (or have already deleted it) before the update
> locks it but if they do you can insert your row without worrying about
> anyone else inserting a conflicting entry since you're still holding a
> lock on the page they'll need to insert the btree entry on and have
> been holding it continuously for the whole operation.

I think that such a lock would also be useful for improving the FK 
deadlock issues we have.

-- 
                                   -- Josh Berkus
                                      PostgreSQL Experts Inc.
                                      http://www.pgexperts.com