How do aggregate projections affect the load performance?
Question from The shortest path to Vertica: Best practices for data warehouse migration & ETL@marcothesane @Maurizio
They affect the load performance like any additional projection.
If you come from another database than, think of adding indexes, and the effect of that - or , for DBMSs that support that, incrementally updating an aggregate Materialized View.
So if you update your base table once a day and run one aggregate report once a day, you might not want to do it. But if you have hundreds of reports daily needing the pre-aggregated data, you will gladly invest the additional workload at load time.