Re: Tablespace setup issue

On 11/21/19 6:48 AM, Sébastien Bihorel wrote:
> Hi,
> 
> I am new to this list and reaching out because I am having troubles 
> setting up a local PostgreSQL database on my laptop. Maybe, as a 
> preamble, I should say that I am pretty much a novice trying to teach 
> myself and get practical experience about database and SQL queries (I 
> have some general idea about relational DB structure and operation but 
> no actual experience creating a DB or writing SQL queries).
> 
> Some background about my setup:
> - OS: my laptop runs Linux Mint 19.1 (a flavor of ubuntu 18.04); psql 
> 12.1 was installed along with pgadmin 4. There is a single user (ie, 
> sebastien) on this machine and the group postgres exists.
> - database: I have successfully created the new superuser sebastien
>                                     List of roles
>   Role name |                         Attributes                         
> | Member of
> -----------+------------------------------------------------------------+-----------
>   postgres  | Superuser, Create role, Create DB, Replication, Bypass RLS 
> | {}
>   sebastien | Superuser, Create DB                                     
>   +| {}
>             | Password valid until infinity                              |
> 
> I have also successfully created a database (sebastien) for the new 
> superuser sebastien, and a schema (test) within this database.
> 
> Now, I would like to assign a particular disk location for the 
> tablespace used by this database but I am getting all kinds of errors 
> apparently linked to folder permissions.
> 
> The location is /home/sebastien/data/pgdata96_sebastien has the 
> following properties:
> 
> /home/sebastien/data $ ls -l
> drwxr-xr-x 2 sebastien postgres 4096 Nov 19 09:14 pgdata96_sebastien
> 
> Starting psql as sebastien, I tried the following requests and got the 
> following errors:
> 
> sebastien=# CREATE TABLESPACE sebdata LOCATION 
> '/home/sebastien/data/pgdata96_sebastien';
> ERROR:  could not set permissions on directory 
> "/home/sebastien/data/pgdata96_sebastien": Permission denied
> sebastien=# ALTER DATABASE sebastien set TABLESPACE 
> '/home/sebastien/data/pgdata96_sebastien';
> ERROR:  syntax error at or near "'/home/sebastien/data/pgdata96_sebastien'"
> LINE 1: ALTER DATABASE sebastien set TABLESPACE '/home/sebastien/dat...
> 
> The manual states "The location must be an existing, empty directory 
> that is owned by the PostgreSQL operating system user." So, I am not 
> sure what I am doing wrong. Web searches ran on these error messages did 
> not enlighten me more...

As it stands now the directory allows you(sebastien) writes on that 
directory. That is not the same as the Postgres system user, which I 
assume is postgres. You need to verify this and also who is part of 
postgres group and adjust the directory permissions to give the postgres 
system user full writes. The thing to remember is that the Postgres 
users(postgres, sebastien) are not the same as the system users even if 
they have the same name.

> 
> I would greatly appreciated any pointers to reference material on these 
> issues or advises on how to approach this.
> 
> Thank you in advance for your time.


-- 
Adrian Klaver
adrian.klaver@aklaver.com