You have an Azure SQL database that stores sales data and contains tables named Sales...

Sales → A clustered columnstore index

Products → A clustered rowstore index

For Sales , the correct choice is a clustered columnstore index . Microsoft identifies clustered columnstore indexes as the standard storage choice for large fact tables and analytical/data-warehouse workloads . The Sales table is 10 TB, loaded in nightly batches, and its reporting queries scan large portions of the table and perform aggregations such as SUM(TotalSale) . Those are exactly the workload characteristics that benefit from columnstore storage, batch-mode execution, aggregate pushdown, and high compression. Microsoft also notes that clustered columnstore indexes can provide substantial storage reduction compared with traditional uncompressed rowstore structures, which directly supports the requirement to minimize storage requirements .

For Products , the correct choice is a clustered rowstore index . Microsoft states that rowstore B-tree indexes perform best for point lookups, equality searches, and small-range retrieval , whereas columnstore is optimized for large analytical scans. Since Products is relatively small and primarily supports point lookups and joins to Sales , a rowstore structure is the better fit.

A nonclustered columnstore index would retain the underlying rowstore and add another compressed copy of selected columns, increasing storage. That is more appropriate for real-time analytics over an OLTP table, not for this dedicated large analytical fact table.