- Interactive: Typically a few joins and some very selective predicates.
- E.g., find one customer and join to related information.
- Index Nested Loops is designed for this case.
- Join with reference table: The index lookup is essentially free.
BNL, SM costs are essentially scanning the larger table.
- Costs would go way down if there's a selective predicate and index.
- Analytic: No avoiding large joins.
- Index lookups are pretty awful -- lots of random access.
- Sort merge is often a good choice.