> WAL would provide the framework to do something like that, but I still
> say it'd be a bad idea. What you're describing is
> irrevocable-once-it-starts DROP COLUMN; there is no way to
> roll it back.
> We're trying to get rid of statements that act that way, not add more.
Yes.
> I am not convinced that a 2x penalty for DROP COLUMN is such a huge
> problem that we should give up all the normal safety features of SQL
> in order to avoid it. Seems to me that DROP COLUMN is only a
> big issue during DB development, when you're usually working with
> relatively small amounts of test data anyway.
Here I don't agree, the statement can also be used for an application version
upgrade. Thus seen in SAP/R3 with tables > 30 Gb.
My conclusion would be that we need both:
1. a fast system table only solution with physical/logical column id
2. a tool that does the cleanup (e.g. vacuum)
Andreas