In this tutorial, we will attempt the various possible causes of this error and some potential fixes for this error. However, it is good to remember that this error can occur due to several occurrences. If the steps that are outlined in this post do not resolve your issue, consider the extra troubleshooting techniques.
Possible Causes of this Error
The following are some possible causes of this error in PostgreSQL:
Postgres Role Does Not Exist – The main cause of this error is that the “postgres” role is not created in the database. By default, PostgreSQL creates a superuser role named “postgres” during installation, but the role may have been deleted.
Casing – Another possible cause of this error is an incorrect role name. It is good to keep in mind that PostgreSQL is case-sensitive. Hence, when providing the username/role, ensure that you give the value in lowercase.
Database migration or import – If you’re migrating or importing a database from another system, the “postgres” role might not exist in the new environment.
The enumerated causes are the possible causes of the “role “postgres” does not exist” when working with PostgreSQL databases.
Let us explore the possible solutions for this type of error.
Fix #1: Create the Postgres Role
If the role doesn’t exist, we can create it using the CREATE ROLE command in PostgreSQL. We can do this by connecting to the PostgreSQL server as an existing superuser or a user that can create the database roles.
You can then invoke the CREATE ROLE on the server:
This should create a new database role called “postgres” on the server.
Next, grant the necessary permissions to the defined role.
Fix #2: Grant the Sufficient Permissions
In some cases, the role may exist on the server but instead lacks sufficient permissions to perform the actions on the database.
To fix this, you can connect to the database as an existing user and execute the following command:
The command should assign all permissions to the postgres user on the defined database.
Fix #3: Initialize the Database
As mentioned, PostgreSQL performs the initialization operations after the installation is complete. However, if the initialization fails, you may be left with unconfigured operations such as the missing postgres role.
To fix this, you can re-initialize the server to default using the “initdb” command. To learn more, you can check the tutorial on https://linuxhint.com/postgres-initdb regarding this command.
This tutorial explores the causes of the “role “postgres” does exist” error in PostgreSQL. We also determined how we could resolve this error by attempting various solutions.