Resolving the FATAL: role 'postgres' does not exist Error in PostgreSQL Installation

Learn how to troubleshoot and resolve the `FATAL: role "postgres" does not exist` error when installing a new PostgreSQL instance on Windows Server.
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Troubleshooting the FATAL: role "postgres" does not exist Error in PostgreSQL

Setting up a PostgreSQL server can sometimes lead to perplexing errors, especially when configuring multiple instances. One common issue arises when you try to connect to a PostgreSQL instance and receive the error message: FATAL: role "postgres" does not exist. This guide will walk you through the steps to understand and resolve this problem.

Understanding the Issue

When you encounter this error, it usually means that the superuser account you are trying to access, in this case the role postgres, has not been created. This can happen during the initialization of the database if the initdb command is executed without specifying a superuser name.

Common Scenario

In a situation where a user tries to set up a second instance of PostgreSQL, they might:

Create a data directory.

Initialize the database.

Start the PostgreSQL instance.

Attempt to connect using the postgres user.

If the database was initialized without the -U postgres option, the default superuser will reflect the current operating system user, which is friazsa instead of postgres. This is likely the situation causing the error you encountered.

Steps to Resolve the Error

Here’s how to resolve the FATAL: role "postgres" does not exist error:

1. Access Your Data Directory

If you have established the PostgreSQL data directory at F:\PostgreSQL\Data_12_2, it’s essential to know that all configurations and database objects are stored there.

2. Delete the Current Database (Optional)

Assuming you haven't populated the database with critical data, you may need to delete the existing initialization. Use the following steps cautiously:

Navigate to your data directory and delete any pre-existing files related to your database.

3. Reinitialize the Database with the Correct Superuser

To ensure that the superuser postgres is created, execute the initdb command with the -U option as shown below:

[[See Video to Reveal this Text or Code Snippet]]

Here, -D specifies the data directory.

-U postgres creates the user postgres as the superuser.

-W will prompt you to set a password for the postgres user.

4. Start the PostgreSQL Instance

Once the database has been reinitialized with the correct superuser account, you can start the PostgreSQL instance using the following command:

[[See Video to Reveal this Text or Code Snippet]]

5. Connecting to the PostgreSQL Instance

You can now attempt to connect to the PostgreSQL instance using the postgres superuser with the command:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, you should be able to resolve the FATAL: role "postgres" does not exist error and successfully connect to your PostgreSQL instance. Always remember that initializing the database with the correct superuser is crucial for smooth operation.

If you have any other queries or need further assistance, feel free to reach out. Happy database managing!