How To Install PostgreSQL 12 on Ubuntu 20.04
Learn how to install PostgreSQL 12 on Ubuntu 20.04. PostgreSQL is an open-source object-relational database management system (ORDBMS)
Introduction
In this tutorial, we learn how to install PostgreSQL 12 on Ubuntu 20.04 (Focal Fossa).
PostgreSQL, or usually called Postgres, is an open-source object-relational database management system (ORDBMS) with an emphasis on extensibility and standards compliance.
PostgreSQL is ACID-compliant and transactional. It is developed by PostgreSQL Global Development Group (PGDG) that consists of many companies and individual contributors. PostgreSQL released under the terms of PostgreSQL license.
PostgreSQL 12 was released on 18 October 2018. Major enhancements in PostgreSQL 12 includes:
- Increased Robustness and Performance for Partitioning
- Transactions Supported in Stored Procedures
- Enhanced Capabilities for Query Parallelism
- Just-in-Time (JIT) Compilation for Expressions
- General User Experience Improvements
Prerequisites
This tutorial assume you already satisfy the following requirements:
- A machine with fresh install of Ubuntu Server 20.04. It can be A virtual machine locally using Virtualbox, VMWare workstation or VMWare Fusion, KVM, Xen, or a virtual machine in the cloud like DigitalOcean or Linode.
- A non-root user with sudo privileges or a root user access. If you’re usig root user remove
sudofrom each command on this tutorial.
Step 1 — Update Base Systems
Since this is a fresh install of Ubuntu Server 20.04, before we install PostgreSQL 12, let’s update our system to the latest update.
sudo apt-get update
sudo apt-get -y upgrade
```bash
After we upgrade our base system, now it's time to install PostgreSQL 12.
Since Ubuntu 20.04 doesn't have PostgreSQL 12 in [its repository][3], we need to add oficial PostgreSQL repository so we can install PostgreSQL 12.
## Step 2 — Import Repository Signing Key {#h-step-2-import-repository-signing-key}
The PostgreSQL team is using GPG to sign downloadable packages from the PostgreSQL website.
We add PostgreSQL public GPG key so apt can verify that packages downloaded from PostgreSQL repository are not tampered or corrupt.
Add PostgreSQL GPG public key using the command below.
```bash
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -You should get OK output for command above.
If you got the different output, you need to fix the error first before continue to the next step.
Step 3 — Add PostgreSQL 12 repository
After adding PostgreSQL release keys, we create a new repository configuration for PostgreSQL using the command below.
echo "deb http://apt.postgresql.org/pub/repos/apt/ $(lsb_release -cs)-pgdg main" | sudo tee /etc/apt/sources.list.d/postgresql-pgdg.list > /dev/null
```bash
Refresh apt metadata using the command below.
```bash
sudo apt-get updateStep 4 — Install PostgreSQL 12
We’re ready to install PostgreSQL 12. Use the command below to install PostgreSQL 12 on Ubuntu 20.04.
sudo apt-get install postgresql-12
```bash
Alternative method to install PostgreSQL 12 on Ubuntu 20.04 is using apt command
```bash
sudo apt install postgresql-12Only 4 steps needed to install PostgreSQL 12 on Ubuntu 20.04. We learn how to check and verify and managing PostgreSQL 12 installation in the next few sections.
Verify PostgreSQL 12 Installation on Ubuntu 20.04
We can check PostgreSQL 12 packages that already installed using the command below.
dpkg -l | grep postgresql
```bash
## Check PostgreSQL 12 Listening Ports {#h-check-postgresql-12-listening-ports}
By default, PostgreSQL listens on port 5432. We can use netstat to check whether there is a process listening on port 5432.
```bash
sudo netstat -naptu | grep 5432Another method is to check whether there is a process named postgres listening on a port.
sudo netstat -naptu | grep postgres
```bash
Alternative to `netstat`, We can use `ss` command below to check whether there is a process listen on PostgreSQL default port 5432.
```bash
sudo ss -atnp | grep 5432We can also use ss to check whether there is a process named postgres listening on a port.
sudo ss -atp | grep postgres
```bash
The last output above shows there is also a connection to ephemeral UDP port from local. According to [this thread on PostgreSQL mailing lists][4], this is PostgreSQL stats collector that use UDP to send and receive stats data locally.
## Checking PostgreSQL Process {#h-checking-postgresql-process}
We can ue `ps` command to check what processes currently running with name contain postgres.
```bash
ps -aux | grep postgresCheck PostgreSQL 12 resource usage like CPU and memory usingtop command.
top -u postgres
```bash
## Managing PostgreSQL 12 Services on Ubuntu 20.04 {#h-managing-postgresql-12-services-on-ubuntu-20-04}
Check `postgres` service status using command below.
```bash
sudo service postgresql statusWe can also use systemctl command to check PostgreSQL service status.
sudo systemctl status postgresql
```bash
Using both commands above you see `active (exited)` on the `Active:` line. This happens because systemd doesn't know the status of each PostgreSQL cluster running on the instance. One instance / installation of PostgreSQL can run mutliple clusters od PostgreSQL.
We can check, list of PostgreSQL clusters running on our machine using the command below.
```bash
pg_lsclustersThere is one cluster running on our machine. The cluster named main running PostgreSQL 12. To check this cluster service status, we can use the command below.
sudo service postgresql@12-main status
```bash
As an alternative to service, we can use systemctl to check this cluster status.
```bash
sudo systemctl status postgresql@12-mainStop PostgreSQL service using the command below.
sudo systemctl stop postgresql
```bash
Start PostgreSQL service using the command below.
```bash
sudo systemctl start postgresqlRestart PostgreSQL service using the command below.
sudo systemctl restart postgresql
```bash
Reload PostgreSQL service using the command below.
```bash
sudo systemctl reload postgresqlConnect to PostgreSQL using psql
Now let’s connect to the PostgreSQL 12 server using psql client application.
By default, postgres create system user named postgres. There is also role in postgresql database named postgres wth superuser permission.
Switch to postgresql user.
sudo su - postgres
```bash
After switching to postgres user, we can connect using `psql` command.
To list all databases in PostgreSQL we can use `\l` command.
To list all users in PostgreSQL we can use `\du` command.
To exit from `psql` we can use `\q` command.
To exit from `postgres` user type `exit` or `CTRL+D`
## Change postgres User Password {#h-change-postgres-user-password}
Now we're on our own linux user. Let's try to login to `localhost` or `127.0.0.1`.
```bash
$ psql -U postgres -W -h 127.0.0.1
Password for user postgres: It prompts for a password. Since we haven’t set any password, let’s leave it empty. We get the error message below.
psql: fe_sendauth: no password supplied
```bash
Since we cannot login without providing password, we set new password for `postgres` user. Change user to `postgres` user like shown above and use psql to connect to PostreSQL.
After logging in, type `\password`. Enter new password and confirmation password for user `postgres`.
When we login again to `localhost` or `127.0.0.1` and provide a password, we can log in successfully.
## Uninstall PostgreSQL 12 from Ubuntu 20.04 {#h-uninstall-postgresql-12-from-ubuntu-20-04}
In this section, we learn how to uninstall PostgreSQL 12 and its dependencies on Ubuntu 20.04 completely.
Please be careful when running steps in this section since this will stop your PostgreSQL database server.
Use the command below to uninstall all PostgreSQL 12 packages, both server, and client.
```bash
sudo apt-get remove postgresql-12 \
postgresql-client-12 \
postgresql-client-common \
postgresql-commonRemove the PostgreSQL data directory using the command below.
rm -rf /var/lib/postgresql/
```bash
Remove PostgreSQL 12 configuration directories using the command below.
```bash
rm -rf /etc/postgresql
rm -rf /etc/postgresql-commonPostgreSQL 12 References
You can follow the links below to learn more about PostgreSQL 12 from PostgreSQL official documentation.
Related Tutorials
- Install PostgreSQL 13 on Ubuntu 20.04
- Install PostgreSQL 11 on Ubuntu 20.04
- Install PostgreSQL 10 on Ubuntu 20.04
- Install PostgreSQL 9.6 on Ubuntu 20.04
Conclusion
In this tutorial, we learn how to install PostgreSQL 12 on ubuntu 20.04. We also learn managing PostgreSQL services, using tools like netstat, ss, ps, and top to check PostgreSQL service.
After that, we learn how to connect to PostgreSQL 12 server using psql client, changing postgres superuser password, and in the end, we learn how to uninstall PostgreSQL 12. I hope this is useful for initiating your journey to PostgreSQL 12.