Re: Optimization of vacuum for logical replication

On 22.08.2019 6:13, Kyotaro Horiguchi wrote:
> Hello.
>
> At Wed, 21 Aug 2019 18:06:52 +0300, Konstantin Knizhnik <k(dot)knizhnik(at)postgrespro(dot)ru> wrote in <968fc591-51d3-fd74-8a55-40aa770baa3a(at)postgrespro(dot)ru>
>> Ok, you convinced me that there are cases when people want to combine
>> logical replication with streaming replication without slot.
>> But is it acceptable to have GUC variable (disabled by default) which
>> allows to use this optimizations?
> The odds are quite high. Couldn't we introduce a new wal_level
> value instead?
>
> wal_level = logical_only
>
>
> I think this thread shows that logical replication no longer is a
> superset(?) of physical replication. I thougt that we might be
> able to change wal_level from scalar to bitmap but it breaks
> backward compatibility..
>
> regards.
>

I can propose the following patch introducing new level logical_only.
I will be please to receive comments concerning adding new wal_level and
possible problems caused by it.

--
Konstantin Knizhnik
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company