Doing a little digging into why South migration was so slow on production data I found that it's doing a separate ALTER TABLE for each column added to the table. In the case of our larger tables they have tens of millions of rows, and I'm adding quite a few columns, so it ends up being very slow.
Is there a way to combine the multiple ALTER TABLE statements South produces into a single statement, and if so would that be faster than several individual statements (I assume it would)?
It looks like there isn't a way to get South to print the SQL it uses. Are there any tricks for getting even partial SQL from south? I can hand-assemble the alter table if I can get the individual parts.