Re: vacuum, performance, and MVCC

Jonah H. Harris wrote:
> On 6/23/06, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > What I see in this discussion is a huge amount of "the grass must be
> > greener on the other side" syndrome, and hardly any recognition that
> > every technique has its downsides and complications.
> 
> I'm being totally objective.  I don't think we should abandon
> PostgreSQL's overall design at all, because we do perform INSERTs and
> DELETEs much better than most systems.  However, I've looked at many
> systems and how they implement UPDATE so that it is a scalable
> operation.  Sure, there are costs and benefits to each implementation,
> but I think we have some pretty brilliant people in this community and
> can come up with an elegant design for scalable UPDATEs.

I think the UPDATE case is similar to the bitmap index scan or perhaps
bitmap indexes on disk --- there are cases we know can not be handled
well by our existing code, so we have added (or might add) these
features to try to address those difficult cases.

--  Bruce Momjian   bruce@momjian.us EnterpriseDB    http://www.enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +