Question

A data engineering team runs Amazon Redshift for a retail analytics warehouse. The two largest tables are a 5 TB fact_sales table and a 4 TB fact_returns table, both joined frequently on the customer_id column in nightly reporting queries. Query monitoring shows heavy data redistribution (DS_BCAST_INNER and DS_DIST_BOTH steps) during these joins, causing long runtimes. Which schema design change will most effectively reduce the data movement during these joins?

Accepted Answer

Set the distribution style to KEY on customer_id for both fact_sales and fact_returns.

Answer

Set the distribution style to ALL on both fact_sales and fact_returns.

Answer

Set the distribution style to EVEN on both fact_sales and fact_returns and add a sort key on customer_id.

Answer

Create a compound sort key on customer_id for both tables while keeping the default AUTO distribution.