unable to create user postgres: role "postgres" does not exists

Question

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

@A.H. The command `pg_lsclusters` was not found. It asked me to install `postgresql-common` package. I tried doing as root user and i got an error. Its tried removing `postgres-xc` and `dpkg: error processing postgres-xc (--remove):` and then it exit. — Kaushik Thirthappa, Mar 24 '13 at 12:11

score 9 · Accepted Answer · answered Mar 25 '13 at 07:37

9

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.

answered Mar 25 '13 at 07:37

Kaushik Thirthappa

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I had a similar issue. When uninstalling postgresql, make sure to stop all postgres processes, delete the unix user `postgres`, and also delete the lock files in `/var/run/postgresql`. – Sergey Orshanskiy May 29 '14 at 23:21
@SergeyOrshanskiy thanks for that. I remember i had eventually solved by doing pretty much what you said. :) – Kaushik Thirthappa May 30 '14 at 13:06
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postgres-xc apparently messed up my postgres setup as well. Same fix worked for me! – Dan Burton Sep 20 '14 at 20:20

1ac0 · Answer 2 · 2013-03-24T08:45:12.917

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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.

edited Mar 24 '13 at 08:45

answered Mar 23 '13 at 20:38

1ac0

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yeah. I am following the steps but i am unable to create a user. The role `postgres` does not exist to create the role `postgres`. Thats what is confusing me. any idea ? – Kaushik Thirthappa Mar 24 '13 at 05:49
@Ladislav: Debian (and therefore also Ubuntu) has custom scripts and conventions for managing PostgreSQL databases and clusters. Using the plain PG-commands will do more harm than it is good. Especially for non-experts. – A.H. Mar 24 '13 at 09:58
@A.H. not know about debian and ubuntu, i'm using slackware. with `initdb` you won't harm your instalation, it's for creating database cluster. it will create files in `/usr/local/pgsql/data`, if something goes wrong you can remove it and go from start. – 1ac0 Mar 24 '13 at 10:09
The problem: This new database might not be picked up at reboot. And having multiple database versions in parallel will not work. Multiple clusters will not work. And so on. Do **you** want to sort out the mess via chat if _anything_ will not work? – A.H. Mar 24 '13 at 10:18
@A.H.i would love to chat and seek help ! – Kaushik Thirthappa Mar 24 '13 at 11:58

unable to create user postgres: role "postgres" does not exists

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