Re: Nested transactions and tuple header info

On Sun, Jun 13, 2004 at 01:22:05PM -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre@dcc.uchile.cl> writes:
> > Not sure how to fix this -- I'm not even sure what the exact problem is,
> > because it's trying to insert the oid of a toast table in
> > pg_class_oid_index during the first ALTER TABLE ... CREATE TOAST TABLE.
> > Why would it see an old tuple with the same value, I don't know.
> 
> This is probably an UPDATE operation not an INSERT.  There are quite a
> few paths through CREATE TABLE that involve repeated updates of the
> new pg_class row.

Huh, right.

> I would think however that these changes would occur as successive
> commands of a single transaction, not as subtransactions, unless you've
> done something odd to CommandCounterIncrement.

Right, but I've taken the XMAX_IS_XMIN bit and replaced it with the
phantom Ids idea.  Probably this problem wouldn't have shown up if I
hadn't done that, but we need to cope anyway.

-- 
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"La principal característica humana es la tontería"
(Augusto Monterroso)