Re: [HACKERS] Logical replication in the same cluster

Tom Lane wrote:
> Petr Jelinek <petr.jelinek@2ndquadrant.com> writes:
>> On 26/04/17 18:59, Bruce Momjian wrote:
>>> ... it just hangs.  My server logs say:
> 
>> Yes that's result of how logical replication slots work, the transaction
>> that needs to finish is your transaction. It can be worked around by
>> creating the slot manually via the SQL interface for example and create
>> the subscription using WITH (NOCREATE SLOT, SLOT NAME = 'your slot') .
> 
> If that's a predictable deadlock, I think a minimum expectation is that
> the system should notice it and throw an error, not just hang.  (Then
> the error could give a hint about how to work around it.)  But the case
> Bruce has in mind doesn't seem like a crazy use-case to me.  Can't we
> make it "just work"?

+1

I think that many people who start experimenting with logical replication
will run into this (like I did).

If nothing else, it's bad PR.
People will get the first impression that logical replication doesn't
work well.

Yours,
Laurenz Albe