Unless you really need the space, I suggest leaving the columns there. Fewer cha...

russell on Dec 27, 2008 | parent | context | favorite | on: Ask HN: How do big web sites roll out new versions...

Unless you really need the space, I suggest leaving the columns there. Fewer chances for error. If your columns are nullable, the amount of space taken up by an obsolete column tends to one byte, particularly if old data is deleted.