 
> > This is wrong assumption. If
> > 
> > 1st client executes UPDATE t SET a = 1 WHERE b = 2;
> > 2nd client executes UPDATE t SET a = 2 WHERE b = 2;
> > 
> > at "the same time" you don't know in what order these
> > queries will be executed on two different servers (because
> > you can't control what transaction will lock record(s)
> > for update first).
> 
> I guess we would need two phase commit in this case. Then it could be 
> guaranteed.
>
 
I'm not sure 2PC would guarantee order here.  There is 
potential for a dead lock across system boundary in this 
example.  If the pre commit messages were sent at the same 
time which server would lock the resource?
 

Darren


Thu, 7 Nov 2002 11:15:38 -0500
<darren@up.hrcoxmail.com>
Re: [HACKERS] Database replication... - Mission Critica