Re: [HACKERS] DROP SUBSCRIPTION and ROLLBACK

On Wed, Feb 8, 2017 at 1:30 AM, Fujii Masao <masao.fujii@gmail.com> wrote:
> On Wed, Feb 8, 2017 at 12:26 AM, Petr Jelinek
> <petr.jelinek@2ndquadrant.com> wrote:
>> For example what happens if apply crashes during the DROP
>> SUBSCRIPTION/COMMIT and is not started because the delete from catalog
>> is now visible so the subscription is no longer there?
>
> Another idea is to treat DROP SUBSCRIPTION in the same way as VACUUM, i.e.,
> make it emit an error if it's executed within user's transaction block.

It seems to me that this is exactly Petr's point: using
PreventTransactionChain() to prevent things to happen.

> Also DROP SUBSCRIPTION should call CommitTransactionCommand() just
> after removing the entry from pg_subscription, then connect to the publisher
> and remove the replication slot.

For consistency that may be important.
-- 
Michael