In a query profile, which condition indicates a join explosion?

• A. 0.03 MB bytes were scanned
• B. There is a join explosion
• C. Poor partition pruning
• D. There is an issue with the profile

Answer: (B)

Join explosion happens when a join step ends up producing far more rows than expected, often because the join condition is missing or not selective enough, leading to many combinations (a near Cartesian product). In a query profile, this shows up as the join operation generating a much larger actual row count or data moved than anticipated, signaling inefficient processing and potential performance issues. That direct indication—“There is a join explosion”—is the clear marker that something went wrong with the join step. The other options describe different issues (small data scanned, poor partition pruning, or a generic profile problem) that don’t specifically point to a problematic join.