On Thu, 9 Jan 2003, Jack Flak wrote:
> Stephan,
>
> That's very interesting! I didn't even know about these other "hidden"
> fields. How many others are there?
Let's see, I think the set is
ctid, oid, xmin, cmin, xmax, cmax, tableoid
IIRC,
ctid is basically like a physical pointer to where the row actually is
oid you know
xmin - transaction that made the row
cmin - command counter in that transaction that made the row
xmax, cmax - like xmin, cmin but for the transaction that removes it
tableoid - which table it belongs to (for inheritance)
Cmin and xmax share storage, and it looks like xmin/xmax are of a type
that you can't actually do much with from an SQL statement.