Quickly making a column non-nullable (without a table scan) - Mailing list pgsql-general

Hi,

I have an index on a column that can be nullable. I decide the column
shouldn't be nullable anymore. So I alter the column to be not
nullable.

That "alter column" query does a full table scan, which can be painful
for large tables.  Couldn't that index be used instead?

Thanks,
Joe