upgrade a database

Hi, sorry but it's hard to say exactly what's happening without looking at the specifics (if you have an AWS support plan, I'd advise opening a support case).

But anyway, if the console is not helping, I'd try the AWS CLI next, with this command:

$ aws rds modify-db-instance --db-instance-identifier myinstancenamehere --no-enable-performance-insights --apply-immediately

As long as disabling Performance Insights is the only modification, there is no downtime to the database instance.

Hope this helps!