> > update a set a=a+1 where a>2;
> > ERROR:  Cannot insert a duplicate key into unique index a_pkey
> 
> This is a known problem with unique contraints, but it's not
> easy to fix it.

Yes, it requires dirty reads.

Vadim

Wed, 20 Jun 2001 09:50:46 -0700
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM>
RE: [BUGS] Update is not atomic