Re: [HACKERS] logical replication and PANIC during shutdowncheckpoint in publisher

On 5/2/17 10:08, Michael Paquier wrote:
> On Tue, May 2, 2017 at 9:30 PM, Peter Eisentraut
> <peter.eisentraut@2ndquadrant.com> wrote:
>> On 5/2/17 03:11, Petr Jelinek wrote:
>>> logical decoding can theoretically
>>> do HOT pruning (even if the chance is really small) so it's not safe to
>>> start logical replication either.
>>
>> This seems a bit impossible to resolve.  On the one hand, we want to
>> allow streaming until after the shutdown checkpoint.  On the other hand,
>> streaming itself might produce new WAL.
> 
> It would be nice to split things into two:
> - patch 1 adding the signal handling that wins a backpatch.
> - patch 2 fixing the side cases with logical decoding.

The side cases with logical decoding are also not new and would need
backpatching, AIUI.

>> Can we prevent HOT pruning during logical decoding?
> 
> It does not sound much difficult to do, couldn't you just make it a
> no-op with am_walsender?

That's my hope.

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