"We have an RDS instance hosted for Aurora PostgreSQL, specifically using the 'db.r5.xlarge' instance type. When we initially set up the RDS instance, a default user named 'rdsadmin' was automatically created with the 'SUPERUSER' role.
During the setup, we also created a master user named 'X'. However, 'X' does not have 'SUPERUSER' permissions.
Our goal is to assign the 'pg_read_server_files' role to the user 'X'. The challenge we face is that we don't have the login credentials for the 'rdsadmin' user since it was a default root user provided by AWS during the RDS instance creation.
We attempted to use the command "GRANT pg_read_server_files to X;", but we encountered an error message: "ERROR: Cannot issue GRANT on the 'pg_read_server_files' role. Detail: Cannot GRANT on the 'pg_read_server_files' role without being a member of the role."
Are there any possible workarounds to assign a new role to an existing user given this situation?"