Brian McCane <bmccane@mccons.net> writes:
> I assume that if I do it in a BEGIN..COMMIT block I won't lose
> anything, but I am not sure if a "DROP INDEX" can be rolled back.
DROP INDEX can be rolled back in the same releases that allow DROP
TABLE to be rolled back. I think we allowed that beginning in
7.0, but check the release notes.
So basically you'd want
BEGIN;
DROP INDEX foo;
either CREATE INDEX ...
or ALTER TABLE ADD PRIMARY KEY ...;
COMMIT;
Note this will imply peak disk usage equal to size of old index
plus size of new, since the old file can't physically be removed
till commit.
regards, tom lane
