Application-level tags (tagName = tagValue) could be added to tables and namespaces, to allow applications to set application-level metadata about a namespace or table.
Use cases include management for billing, administrator notes, date created, last ingest time, stats, information about the table's schema... or anything else an application might wish to use tags for.
These tags could be stored in zookeeper, but are probably best stored in the metadata table (probably in a separate reserved area of the metadata table, ~tag) because they could be arbitrarily large and do not need to be persisted in memory.
This feature would include new APIs to manipulate table / namespace metadata. Considerations should be made to ensure users have appropriate permissions to add tags to an object.
This feature could be used to implement