Re: ALTER TABLE SET STATISTICS requires AccessExclusiveLock

On Fri, 2009-08-07 at 15:58 -0400, Alvaro Herrera wrote:
> Tom Lane wrote:
> > Peter Eisentraut <peter_e@gmx.net> writes:
> > > Is there a good reason for $subject, other than that the code is entangled 
> > > with other ALTER TABLE code?
> > 
> > I think it could be lower, but it would take nontrivial restructuring of
> > the ALTER TABLE support.  In particular, consider what happens when you
> > have a list of subcommands that don't all require the same lock level.
> > I think you'd need to scan the list and find the highest required lock
> > level before starting ...
> 
> IIRC there was a patch from Simon to address this issue, but it had some
> holes which he didn't have time to close, so it sank.  Maybe this can be
> resurrected and fixed.

I was intending to finish that patch in this release cycle.

MERGE needs further work if you are looking for a project. It isn't
immediately obvious but MERGE logic is a requirement for maintaining
materialized views, which is why I was working on that.

-- Simon Riggs           www.2ndQuadrant.com