Re: Alter table alter column

[Tom Lane <tgl@xxxxxxxxxxxxx>]

Marc Munro <marc@xxxxxxxxxxxx> writes:
> Am I right in thinking that altering a column from varchar(n) to
> varchar(n+m) requires each tuple to be visited?

Yes.  Doing otherwise would require an unreasonable amount of
data-type-specific knowledge hardwired into ALTER COLUMN TYPE.

			regards, tom lane