The following bug has been logged on the website:
Bug reference: 15916
Logged by: Marnanel Thurman
Email address: thomas(at)thurman(dot)org(dot)uk
PostgreSQL version: 11.4
Operating system: Debian
Description:
This happens with version 11.4-1.pgdg90+1 in
http://apt.postgresql.org/pub/repos/apt/ .
The upgrade process prints this message:
Success. You can now start the database server using:
pg_ctlcluster 11 main start
But the server is restarted automatically, immediately afterwards. So the
message is confusing, and should be suppressed.