Major Description
Ideally, an administrator would have the ability to restrict the visibility of workspaces based on the FS permissions that underly those workspaces. Currently it appears we only honor this for 'show tables' , but not for 'show databases'.
Without this functionality (or something that gives an equivalent result), users will be able to see any and all workspaces, including ones which administrators may wish to keep 'invisible'. Additionally, when having hundreds (or potentially thousands) of users, seeing all workspaces via 'show databases' is likely to make it difficult for end-users to know what they can and cannot access.