For me, when I saw "
FATAL: the database system is starting up", nothing else hasn't been working: pgAdmin, psql, business apps.Logs has been showing cycles: client connect - worker starts - "the-FATAL-error" - worker shutting down with exit code (1). No any informative errors.
I think, database engine is in some sort of recovery mode after crush, but I was waiting long enough - no CPU or HDD activity. If it's some sort of warning and waiting for me to check consistency and manually reset this mode flag, but then how to do this?!
More important: now problem is not solved, "hot_standby = on" is just workaround letting query databases. But PostgreSQL is still in some strange mode and I don't understand how serious is it and how resolve it correctly.
By "PostgreSQL is still in some strange mode" I mean that setting "hot_standby = off" returns "the-FATAL-error" and nothing works then.
