If you are installing from the Fedora RPM files, a necessary postgres user account (that is, an account with the name of the user running the server on your system) is created for you automatically:
$ fgrep postgres /etc/passwd
postgres:x:26:26:PostgreSQL Server:/var/lib/pgsql:/bin/bash
Otherwise, you need to create a user called postgres during the installation. This user shouldn't have login privileges because only root should be able to use su to become this user and no one will ever log in directly as the user. (Refer to Chapter 10, 'Managing Users,' for more information on how to add users to a Fedora system.) After you have added the user, you can install each of the PostgreSQL RPMs you downloaded using the standard rpm -i command for a default installation.
Initializing the Data Directory in PostgreSQL
After the RPMs are installed, you need to initialize the data directory. To do so, you must first create the data directory and you must be the root user. The following example assumes that the data directory is /usr/local/pgsql/data.
Create the /usr/local/pgsql/data directory (using mkdir) and change the ownerships of the directory (using chown and chgrp) so it is owned by the user postgres. Then use su and, as the user postgres, issue the following commands:
# mkdir /usr/local/pgsql
# chown postgres /usr/local/pgsql
# chgrp postgres /usr/local/pgsql
# su - postgres
-bash-2.05b$ initdb -D /usr/local/pgsql/data
The files belonging to this database system will be owned by user 'postgres'.
This user must also own the server process.
The database cluster will be initialized with locale en_US.UTF-8.
This locale setting will prevent the use of indexes for pattern matching
operations. If that is a concern, rerun initdb with the collation order
set to 'C'. For more information see the Administrator's Guide.
creating directory /usr/local/pgsql/data... ok
creating directory /usr/local/pgsql/data/base... ok
creating directory /usr/local/pgsql/data/global... ok
creating directory /usr/local/pgsql/data/pg_xlog... ok
creating directory /usr/local/pgsql/data/pg_clog... ok
creating template1 database in /usr/local/pgsql/data/base/1... ok
creating configuration files... ok initializing pg_shadow... ok
enabling unlimited row size for system tables... ok
initializing pg_depend... ok
creating system views... ok
loading pg_description... ok
creating conversions... ok
setting privileges on built-in objects... ok
vacuuming database template1... ok
copying template1 to template0... ok
Success. You can now start the database server using:
/usr/bin/postmaster -D /usr/local/pgsql/data
or
/usr/bin/pg_ctl -D /usr/local/pgsql/data -l logfile start
This initializes the database and sets the permissions on the data directory to their correct values.
The initdb program sets the permissions on the data directory to 700. You should not change these permissions to anything else to avoid creating a security hole.
You can start the postmaster program with the following command (make sure that you are still the user postgres):
$ postmaster -D /usr/local/pgsql/data &
If you have decided to use a directory other than /usr/local/pgsql/data as the data directory, you should replace the directory in the postmaster command line with what ever directory you are using.
By default, Fedora makes the PostgreSQL data directory /var/lib/pgsql/data. This isn't a very good place to store the data, however, because most people do not have the necessary space in the /var partition for any kind of serious data storage. Note that if you do change the data directory to something else (such as /usr/local/pgsql/data, as in the examples in this section), you need to edit the PostgreSQL startup file (named postgres) located in /etc/rc.d/init.d to reflect the change.
Creating a Database in PostgreSQL
Creating a database in PostgreSQL is straightforward, but it must be performed by a user who has permissions to create databases in PostgreSQL — for example, initially the user named postgres. You can then simply issue the following command from the shell prompt (not the PSQL client prompt, but a normal shell prompt):
# su – postgres
-bash-2.05b$ createdb
where
The createdb program is actually a wrapper that makes it easier to create databases without having to log in and use psql. However, you can also create databases from within psql with the CREATE DATABASE statement. Here's an example:
CREATE DATABASE database;
You need to create at least one database before you can start the pgsql client program. You should create this database while you're logged in as the user postgres. To log in as this user, you need to use su to become root and then use su to become the user postgres. To connect to the new database, you start the psql client program with the name of the new database as a command-line argument, like so:
$ psql sampledata
If you don't specify the name of a database when you invoke psql, the command attempts
