Re: cascading column drop to index predicates

Tom Lane wrote:

>Rod Taylor <pg(at)rbt(dot)ca> writes:
>
>
>>I think Andreas is trying to argue that if you drop column b from index
>>(a, b) that the index should be converted into index(a) -- assuming of
>>course there isn't already an index(a).
>>
>>
>
>That seems to be well outside the charter of DROP CASCADE. I think we
>either drop or don't drop; we don't go building new indexes, which is
>what this would take. There are also definitional problems --- for
>instance, if the index is UNIQUE, does it transmogrify into a UNIQUE
>constraint on A alone (which would most likely fail)?
>
>

Agreed, auto creation wouldn't be necessary/expected. If you drop,
objects disappear, you don't expect them to morph. But I'd like to be
inhibited to drop the column if it requires a somewhat recreated index
on (a). So IMHO a DROP INDEX [RESTRICT] should drop only dependent
objects if this won't affect others.

Regards,
Andreas