PostgreSQL 12 Beta 4

Hi,

PostgreSQL 12 Beta 4 will be released on 2019-09-12. Please make sure
that fixes for bugs and other open items[1] are committed by the end of
the weekend.

Thanks for all of your efforts in getting PostgreSQL 12 ready for
general availability!

Jonathan

[1] https://wiki.postgresql.org/wiki/PostgreSQL_12_Open_Items