Best practices when combining multiple fact tables?

rjs_docs

Is it better to combine multiple fact tables with a primary key or with a merge operation?
@bat @rbankula

From Optimizing Query Performance and Resource Pool Tuning.

baron42bba

Keep them separate.
Pick one of them as your main table and extend that with the columns of the other table with the https://www.vertica.com/docs/9.3.x/HTML/Content/Authoring/AnalyzingData/FlattenedTables/FlattenedTables.htm feature.