Chris Browne <cbbrowne@acm.org> wrote:
> I'd suggest adding an index
The OP said the table had 15 indexes already. I would guess one of
those could be used. Perhaps it has a primary key....
> update table1 set new_column = [whatever calculation]
> where new_column is null and
> quasi_unique_column in
> (select quasi_unique_column from table1
> where new_column is null limit 1000);
Or, if the primary key (or other unique or quasi-unique existing
index) has multiple columns, this could still be done with:
update table1 set new_column = [whatever calculation]
where new_column is null and
(col1, col2) in
(select col1, col2 from table1
where new_column is null limit 1000);
-Kevin
