Re: Nested transactions and tuple header info

On Wed, Jun 02, 2004 at 10:57:05AM -0400, Bruce Momjian wrote:
> Tom Lane wrote:
>
> > No, I said own xid --- so the "phantom xid" part is still there.  But
> > your idea definitely does *not* work unless you use a single CID
> > sequence for the whole main xact; and I'm still wondering if there's
> > not a simpler implementation possible given that assumption.
> 
> I don't understand why a single counter is needed for phantom xids.  We
> keep the cmin/cmax on the tuple already, and our own backend can look up
> the xmin/xmax that goes with the phantom.

Not sure either way (maybe you are right), but I use the global counter
anyway because some tests would become a very ugly mess if I didn't.  I
think the phantom idea is also simpler with the global counter.

And I see no reason to use local counter.  We certainly are not
hitting the limit with the global counter, as Tom pointed out recently
in a thread about the aborted CID bitmaps.

-- 
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"Crear es tan difícil como ser libre" (Elsa Triolet)