Re: Cannot create role, no default superuser role exists

On 03/10/2016 04:11 PM, Robert McAlpine wrote:
>
> Postgresql 9.5, Ubuntu 14.04.
>
> I broke my ability to access postgres after attemping to install
> postgres-xc (ironic, since I installed that to use pg_ctl to reload my
> pg_hba.conf without restarting the entirety of postgres).

That is available with the stock Postgres, unless I am missing something:

http://www.postgresql.org/docs/9.5/interactive/auth-pg-hba-conf.html
"The pg_hba.conf file is read on start-up and when the main server
process receives a SIGHUP signal. If you edit the file on an active
system, you will need to signal the postmaster (using pg_ctl reload or
kill -HUP) to make it re-read the file."

Did you install postgres-xc over your existing instance?

>
> After doing so I can no longer access my databases via psql or any other
> utilities, getting the error:
>
> FATAL: role "postgres" does not exist
>
> Unfortunately the same error gets thrown if I attempt to use 'createuser'.
>
> The postgres user and role were the only ones able to access postgresql
> server, so altering the permissions in my pg_hba.conf also got me nowhere.
>
> I made a complete copy of the data directory, took a snapshot (it is on

Which data directory, the postgres-xc one or the original Postgres one?

> a vm), then purged postgresql-9.5 and reinstalled, restoring to a dump
> that is a few days old. I thought about copying all the files from the

Installed from a package or source?

The dump was from a pre-xc version of Postgres?

It would seem to me if you reinstalled in default manner you would have
a postgres user available. So where did you get:

FATAL: role "postgres" does not exist

before or after the reinstall?

> data directory (except for the roles table file) into a fresh install
> with a correct default postgres role, but my gut tells me that screwing
> around with those files is doomed to fail.

Yeah, I would hold off doing that until it is clearer what is going on.

>
> I would appreciate any help or thoughts on how to recover access to the
> data.
> --
> Robert McAlpine
> rem(at)pfcta(dot)com <mailto:rem(at)pfcta(dot)com>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com