Column authorization development guidance

[Stephen Carlin]

Hi all,

I'm hoping to get some pointers on how to do authorization for my database
using Calcite.

I have an idea of how to do table level authorization at validation time.
But column level seems a lot more tricky.  What would be the guidance on
when to do column level authorization?  Is that something that is usually
done after RelNode conversion, so that there are 2 authorization steps that
are separated?

Any advice from currently implemented architectures would be appreciated.

Thanks!