Extending a huge database table

I need to add three DOUBLE columns to the end of a InnoDB database table that already has a size of about 100 GB. (Yes, I know.)

The last time I tried (adding the 3 columns in HeidiSQL, then saving the changes), the operation aborted after a while because the harddisk was full (even though about 130 GB are still free). Not sure how the adding of columns is technically done and if there is another way to do it that doesn't require huge temporary data - maybe by submitting an ALTER TABLE. Any suggestions?

-Michael

There is no other way. You can see the ALTER commands in the ALTER code tab on the table designer. Maybe you can optimize it, but I don't guess so.