I think that patch hasn't been commited yet:
https://commitfest.postgresql.org/21/1574/
El jue., 28 mar. 2019 a las 20:37, Eric J. Van der Velden (<
ericjvandervelden(at)gmail(dot)com>) escribió:
> On https://wiki.postgresql.org/wiki/2PC_on_FDW it says I have to set the
> configuration parameter "max_prepared_foreign_transactions" in
> postgresql.conf. When I restart postgres, I see:
>
> LOG: unrecognized configuration parameter
> "max_prepared_foreign_transactions" in file
> "/var/lib/postgresql/data/postgresql.conf" line 689
>
> Thanks,
> Eric.
>