[Feature] postgres__get_columns_in_relation should support materialized views

[adase11]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward extension of existing dbt-postgres functionality, rather than a Big Idea better suited to a discussion

Describe the feature

The macro postgres__get_columns_in_relation (link) only looks at the information_schema.columns to get the column names for the particular relation. This doesn't work for materialized views because information_schema.columns doesn't include information about materialized views. I think that adaptor macro could be enhanced to account for this and potentially look at pg_attribute (docs) instead. Based on this Stack Overflow it looks like its possible. I'm happy to research some more if that's helpful.

Describe alternatives you've considered

I considered reporting this as a bug but I think its more of a feature request. I imagine the information schema choice was intentional and maybe there is something I'm not considering about pg_attribute that you all have already considered that makes it unfeasible. In that case I'd propose documenting this nuance for postgres.

Who will this benefit?

Anyone using the dbt_utils.star macro with postgres (like I was)

Are you interested in contributing this feature?

I'm happy to contribute if this request is accepted

Anything else?

No response

[drewblinn]

Does this solution help you @adase11?
dbt-labs/dbt-codegen#155
dbt-labs/dbt-core#9419

[adase11]

@drewblinn it looks like yes. The implementation of the PR I didn't fully check, but I can look to see if it will cover what I'm looking for (it looks like it intends to). The way I went about it for my custom macro was that I queried the information schema for non-materialized views and pg_attribute only for MVs.

[adase11]

Double checked, the PR looks right to me. Although it looks like that was aimed at dbt-core and the adaptors have been decoupled from dbt-core and so those changes would be better served in this module (dbt-postgres).

[drewblinn]

I also overrode it in our project, but I'll get a PR together to roll these changes out to dbt-postgres the the entire community can reap the benefits! @adase11