OLAP (Online Analytical Processing)

OLAP describes database workloads dominated by complex analytical queries — large aggregations, multi-way joins, and reporting across historical data — as opposed to the many small transactions typical of OLTP.

OLAP queries tend to scan and aggregate large numbers of rows ("total revenue by region by quarter") rather than fetching or modifying a single row. Data warehouses, star schemas, columnar storage, bitmap indexes, and table partitioning are all techniques specifically suited to OLAP workloads.

"OLAP cube" is the classic term for a pre-aggregated, multi-dimensional summary of data built to make this kind of slice-and-dice reporting fast.