How to Install and Use PostgreSQL on Oracle Linux 8

PostgreSQL is a free, open-source, secure, and robust relational database management system. It is specially designed for high-performance and mission-critical applications. PostgreSQL supports SQL and JSON querying and is mainly used for many web and mobile and analytics applications. It is compatible with various platforms using all major languages and middleware. When writing this article, PostgreSQL 14 is the latest version. This version significantly improves the indexing and lookup system that benefits large databases.

This post will show you how to install and secure PostgreSQL on Oracle Linux 8.

Step 1 – Add PostgreSQL 14 Repository

By default, the latest version of PostgreSQL is not included in the Oracle Linux default repository. You can check the default available version in the AppStream repository using the following commands:

dnf update -y

dnf module list postgresql

You should see the list of available versions in the following output:

Oracle Linux 8 Application Stream (x86_64)
Name                         Stream                   Profiles                            Summary                                             
postgresql                   9.6                      client, server [d]                  PostgreSQL server and client module                 
postgresql                   10 [d]                   client, server [d]                  PostgreSQL server and client module                 
postgresql                   12                       client, server [d]                  PostgreSQL server and client module                 
postgresql                   13                       client, server [d]                  PostgreSQL server and client module                 

Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled

You must install the PostgreSQL repo on your system to install the latest PostgreSQL version.

You can install it using the following command:

dnf install https://download.postgresql.org/pub/repos/yum/reporpms/EL-8-x86_64/pgdg-redhat-repo-latest.noarch.rpm

Once the repo is created, you can proceed to the next step.

Step 2 – Install PostgreSQL 14 on Oracle Linux 8

Now, update your repository using the following command:

dnf update -y

Next, disable the default PostgreSQL repo using the following command:

dnf -qy module disable postgresql

Next, install the latest version of PostgreSQL by running the following command:

dnf install postgresql14 postgresql14-server

Once PostgreSQL is installed, you will get the following output:

Last metadata expiration check: 0:00:11 ago on Sunday 29 May 2022 12:33:52 PM EDT.
Dependencies resolved.
==============================================================================================================================================
 Package                               Architecture             Version                             Repository                           Size
==============================================================================================================================================
Installing:
 postgresql14                          x86_64                   14.3-1PGDG.rhel8                    pgdg14                              1.5 M
 postgresql14-server                   x86_64                   14.3-1PGDG.rhel8                    pgdg14                              5.7 M
Installing dependencies:
 lz4                                   x86_64                   1.8.3-3.el8_4                       ol8_baseos_latest                   103 k
 postgresql14-libs                     x86_64                   14.3-1PGDG.rhel8                    pgdg14                              276 k

Transaction Summary
==============================================================================================================================================
Install  4 Packages

Total download size: 7.6 M
Installed size: 32 M
Is this ok [y/N]: 

Next, initialize the PostgreSQL database with the following command:

/usr/pgsql-14/bin/postgresql-14-setup initdb

Sample output:

Initializing database ... OK

Next, start the PostgreSQL service and enable it to start at system reboot with the following command:

systemctl start postgresql-14
systemctl enable postgresql-14

You can check the status of PostgreSQL with the following command:

systemctl status postgresql-14

You should get the following output:

● postgresql-14.service - PostgreSQL 14 database server
   Loaded: loaded (/usr/lib/systemd/system/postgresql-14.service; disabled; vendor preset: disabled)
   Active: active (running) since Sun 2022-05-29 12:35:13 EDT; 8s ago
     Docs: https://www.postgresql.org/docs/14/static/
  Process: 2084 ExecStartPre=/usr/pgsql-14/bin/postgresql-14-check-db-dir ${PGDATA} (code=exited, status=0/SUCCESS)
 Main PID: 2090 (postmaster)
    Tasks: 8 (limit: 23694)
   Memory: 16.7M
   CGroup: /system.slice/postgresql-14.service
           ├─2090 /usr/pgsql-14/bin/postmaster -D /var/lib/pgsql/14/data/
           ├─2091 postgres: logger 
           ├─2093 postgres: checkpointer 
           ├─2094 postgres: background writer 
           ├─2095 postgres: walwriter 
           ├─2096 postgres: autovacuum launcher 
           ├─2097 postgres: stats collector 
           └─2098 postgres: logical replication launcher 

May 29 12:35:13 oraclelinux8 systemd[1]: Starting PostgreSQL 14 database server...
May 29 12:35:13 oraclelinux8 postmaster[2090]: 2022-05-29 12:35:13.577 EDT [2090] LOG:  redirecting log output to logging collector process
May 29 12:35:13 oraclelinux8 postmaster[2090]: 2022-05-29 12:35:13.577 EDT [2090] HINT:  Future log output will appear in directory "log".
May 29 12:35:13 oraclelinux8 systemd[1]: Started PostgreSQL 14 database server.

By default, PostgreSQL listens on port 5432. You can check it with the following command:

ss -antpl | grep 5432

You will get the following output:

LISTEN 0      128        127.0.0.1:5432      0.0.0.0:*    users:(("postmaster",pid=2090,fd=7))
LISTEN 0      128            [::1]:5432         [::]:*    users:(("postmaster",pid=2090,fd=6))

Also Read

How to Secure PostgreSQL Server in Linux

Step 3 – Set a Password Postgres User

By default, the Postgres user’s password is not set, so it is recommended to set a password for security reasons.

To set a password, log in to PostgreSQL with the following command:

su - postgres

Next, set a secure password with the following command:

psql -c "alter user postgres with password 'securepassword'"

Next, exit from the PostgreSQL shell using the following command:

exit

nano /var/lib/pgsql/14/data/pg_hba.conf

local   all             all                                     peer

local   all             all                                     scram-sha-256

systemctl restart postgresql-14

sudo -u postgres psql

psql (14.3)
Type "help" for help.

postgres=# 

CREATE USER testuser WITH CREATEDB CREATEROLE PASSWORD 'passoword';

\du

                                   List of roles
 Role name |                         Attributes                         | Member of 
-----------+------------------------------------------------------------+-----------
 postgres  | Superuser, Create role, Create DB, Replication, Bypass RLS | {}
 testuser     | Create role, Create DB                                     | {}

CREATE DATABASE testdb OWNER testuser;

\l

                                  List of databases
   Name    |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges   
-----------+----------+----------+-------------+-------------+-----------------------
 postgres  | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | 
 template0 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres
 testdb   | testuser    | UTF8     | en_US.UTF-8 | en_US.UTF-8 | 
(4 rows)

postgres=#