i am on ubuntu 12.04 server and i am trying to install postgresql. As of now, i have successfully installed it but unable to configure it. I need to create a role to move ahead and i ran this command in terminal :
root@hostname: createuser -s -r postgres
and it said :
createuser: could not connect to database postgres: FATAL: role "root" does not exist
Fine, so i did :
su - postgres
and then tried again
postgres@hostname: createuser -s -r postgres
and i got the error
createuser: could not connect to database postgres: FATAL: role "postgres" does not exist
and i get the same error when i do
psql -d dbname
Its like a loop, i am unable to create a role postgres because a role postgres does not already exist.
How do i fix this ?
The postgres version seems to be 9.1.x and the ubuntu version is 12.10
Turns out i had installed postgres-xc and postgresql on my machine. I had to knock off postgres-xc completely. And it was a little difficult to do that because, there was always an error --purge remove postgres-xc and the uninstallation could not continue.
There seems to be some kind of a packaging bug. (details on launchpad).
Eventually, i ended up doing this to make it work.
After that i uninstalled postgresql and installed it back to make it work.
Read postgresql tutorial it doesn't matter if it's Ubuntu or other Linux.
EDIT before creating role or anything else on fresh install you need to create database cluster: have you created it?
initdb -D /usr/local/pgsql/data
You need to be logged as user postgres on linux machine. Here is more info.
来源：https://stackoverflow.com/questions/15591749/unable-to-create-user-postgres-role-postgres-does-not-exists