postgres user cannot drop database

Question

Im trying to drop some databases on a postgres 9.6 server, but when I try Im told I am unable to.

I was under the impression that the postgres user was like a superuser.

su postgres
bash-4.2$ psql
could not change directory to "/root": Permission denied
psql (9.6.8)
Type "help" for help.
postgres=> DROP DATABASE d;
ERROR: must be owner of database d
postgres=>

• user1822: As a superuser you can always take ownership of that database, then drop it.
• Jasen: hmm, superusers usally get a =# prompt, not =>.
• Daniel Vérité: You have a previously abandoned question in postgres user is not superuser which seems closely related.
• Magick: Yes youre right. And I think this, and the other problem are probably due to being hacked

Answer 1

The problem with su postgres command, you changed the user to posgress but bash (to be more specific environment) owner still root or the original user, in-order to fix this issue use su - postgres instead of su postgres

• Jasen: with or without - makes no difference to the psql command
• Ahmad Abuhasna: @Jasen your reference please, that - will not do any side effect, here is my references dba.stackexchange.com/questions/40335/… stackoverflow.com/questions/35782366/… serverfault.com/questions/718176/…
• Jasen: ok, but it makes no difference to the database permissions
• Ahmad Abuhasna: @Jasen your reference please
• Jasen: just try it, you will see.