redshift RA3 nodes support cross-db references, but dbt prevents this in compilation

https://github.com/fishtown-analytics/dbt/blob/841b2115a42cc20658ec69ba129d515412993d10/core/dbt/adapters/base/relation.py#L440-L442

this is tricky because there is a long term fork in redshift behavior based on node type. RA3 nodes support cross db references (this is now GA) but gen2 node types do not. the redshift/postgres connector may need to be subclassed for ra3 node types with the db-ref-count omitted. It might be possible to distinguish between node types by issuing a version command.

If simplicity of implementation is preferred, an override could maybe be added to the project.yml spec (like, force-enable-cross-db=true or something as an option which defaults to false for the next release and automatic detection could be added in a future release?

I don’t know the codebase well enough to assess what strategy would create the least tech debt.

[salmonsd]

Following up here, this seems to be resolved in #3408 and should be included is v0.21.

cc: @jtcohen6

[jtcohen6]

You’re right! This will be released in v0.21.0-b1 for starters, and it will require flipping on a ra3: true parameter in the Redshift profile. I’m going to close this issue 😃