Re: ALTER TABLE DROP COLUMN

> The Hermit Hacker <scrappy(at)hub(dot)org> writes:
> > hrmm .. mvcc uses a timestamp, no? is there no way of using that
> > timestamp to determine which columns have/haven't been cleaned up
> > following a crash? maybe some way of marking a table as being in a 'drop
> > column' mode, so that when it gets brought back up again, it is scan'd for
> > any tuples older then that date?
>
> 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.
>
> 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.
>

Bingo!

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