Re: logical replication syntax (was DROP SUBSCRIPTION, query cancellations and slot handling)

On 5/8/17 23:23, Peter Eisentraut wrote:
> The way this uses RESTRICT and CASCADE appears to be backwards from its
> usual meaning. Normally, CASCADE when dropping an object that is still
> used by others will cause those other objects to be dropped. The
> equivalent here would be DROP REPLICATION SLOT + CASCADE would drop the
> subscription.
>
> What we want to simulate instead is an "auto" dependency of the slot on
> the subscription. So you can drop the slot separately (subject to other
> restrictions), and it is dropped automatically when the subscription is
> dropped. To avoid that, you can disassociate the slot from the
> subscription, which you have implemented.
>
> I think we can therefore do without RESTRICT/CASCADE here. If a slot is
> associated with the subscription, it should be there when we drop the
> subscription. Otherwise, the user has to disassociate the slot and take
> care of it manually. So just keep the "cascade" behavior.
>
> Similarly, I wouldn't check first whether the slot exists. If the
> subscription is associated with the slot, it should be there.

Here is your patch amended for that.

--
Peter Eisentraut http://www.2ndQuadrant.com/
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