Oleg Pykhalov <go.wigust@gmail.com> writes:

> Every ‘guix system reconfigure’ I see a message about
> “/var/lib/postgresql/ already exists, skipping creating” if I remember
> correctly.  Do you see this when you use a cluster?  

Yes.

> I don't have a strong opinion for this, but the message is enough, isn't
> it?  Maybe we could say in the documentation to remove data directory in
> any case when you don't need previous data?

I don't find the message explicit enough, in particular it does not
explain that the existing data could cause Postgres to fail.

Finally, it's easy to miss the message in this wall of text.

> I tried ‘sudo su postgres -s /bin/sh’, then:
> --8<---------------cut here---------------start------------->8---
> sh-5.0$ createuser --interface
> sh: createuser: command not found
> --8<---------------cut here---------------end--------------->8---
>
> First of all we could use just ‘sudo’ to get a shell:
>
>     sudo -u postgres -s /bin/sh

I thought I had tried this and it didn't work for whatever reason.  I'll
test again.

> ‘createuser’ and ‘createdb’ are in ‘/gnu/store/…-postgresql-10.13/bin’,
> which is missing in my ‘postgres’ user's profile.

Right, I have postgresql installed in my user profile.

> To fix this we could make ‘postgres’ available by default as in
> https://git.savannah.gnu.org/cgit/guix.git/commit/?id=db65d7447c3adc46e2b24abfc07ae10c6c537df4

I think you meant the postgresql package.  Indeed, that would fix it.
However this means we are "polluting" all user profiles with executables
that are not necessarily wanted by everyone.  Is this desirable?

-- 
Pierre Neidhardt
https://ambrevar.xyz/