Re: DROP SUBSCRIPTION hangs if sub is disabled in the same transaction

On 9/14/17 15:47, Arseny Sher wrote:
> Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
>
>> On 9/13/17 07:00, Arseny Sher wrote:
>>> On the other hand, forbidding to execute disable sub and drop sub in one
>>> transaction makes it impossible e.g. to drop subscription in trigger
>>
>> Disabling a subscription before dropping it isn't very useful, is it?
>> So I'm not sure this is an important use case we need to optimize. We
>> just need to prevent it from hanging.
>
> Not quite so. Currently it is forbidded to set subscription's slot to
> NONE on enabled sub, and the only way to drop sub without touching the
> slot is to run ALTER SUBSCRIPTION SET (SLOT_NAME = NONE) beforehand.
> Practically this means that we have to go through disable sub -> alter
> sub -> drop sub pipeline if we want to left the slot alone or just would
> like to drop sub in transaction block -- with replication slot set the
> latter is impossible.

OK, good point.

Here is a simple patch that fixes this, based on my original proposal
point #4.

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