C1000-065 · Question #1
Which of the following can result in poor report performance?
The correct answer is B. models with outer joins and cross joins. Outer joins and cross joins are computationally expensive operations - cross joins in particular produce a Cartesian product, multiplying row counts and forcing the database to process far more data than necessary, which degrades report performance significantly. Option A is…
Question
Which of the following can result in poor report performance?
Options
- Areports with filters
- Bmodels with outer joins and cross joins
- Cqueries with database only processing
- Dan optimized metadata model
How the community answered
(50 responses)- A2% (1)
- B90% (45)
- C6% (3)
- D2% (1)
Explanation
Outer joins and cross joins are computationally expensive operations - cross joins in particular produce a Cartesian product, multiplying row counts and forcing the database to process far more data than necessary, which degrades report performance significantly. Option A is wrong because filters improve performance by reducing the volume of data returned. Option C is wrong because database-only processing (query pushdown) is a best practice that offloads work to the database engine, which is optimized for it. Option D is wrong because an optimized metadata model is a performance solution, not a problem.
Memory tip: Think of joins by their "explosion potential" - a cross join between two 1,000-row tables produces 1,000,000 rows. If your model is full of outer and cross joins, your reports are dragging that explosion into every query.
Topics
Community Discussion
No community discussion yet for this question.