> > > > Changing data types probably won't appear. I don't know of anyone
> > > > working on it -- and it can be quite a complex issue to get a good
> > > > (resource friendly and transaction safe) version.
> > >
> > > I'd be happy with a non-resource friendly and non-transaction-safe version
> > > over not having the functionality at all... ;)
Certain (imho common) cases could be short circuited to only manipulate the column
definition (including default value), like alter varchar(10) to varchar(20),
or decimal(10) to decimal(20), or even varchar(10) to varchar(5) (which would need
to select all rows, and check that none is actually longer than 5, or abort).
That is what I have seen other db's do. Do it inplace where it is easily possible,
else do a long transaction that rewrites the content.
Andreas