Re: ALTER COLUMN to change GENERATED ALWAYS AS expression?

On Tue, 2023-02-07 at 12:40 -0600, Ron wrote:
> > "The DROP COLUMN form does not physically remove the column, but simply makes it
> > invisible to SQL operations. Subsequent insert and update operations in the table
> > will store a null value for the column. Thus, dropping a column is quick but it
> > will not immediately reduce the on-disk size of your table, as the space occupied
> > by the dropped column is not reclaimed. The space will be reclaimed over time as
> > existing rows are updated.
> >
> > To force immediate reclamation of space occupied by a dropped column, you can
> > execute one of the forms of ALTER TABLE that performs a rewrite of the whole table.
> > This results in reconstructing each row with the dropped column replaced by a
> > null value."
>
> VACUUM FULL doesn't rewrite the table?

It rewrites the table, but it just copies rows rather than reconstructing them.

Yours,
Laurenz Albe