Handling Gaps & Failures:
"In a high-volume integration, you notice that some number sequence values were skipped (gaps in the numbering) after an import or a series of API calls. What are some reasons for missing numbers in an otherwise noncontinuous sequence, and how do you explain or handle these gaps? What changes (if any) would you make if gaps are not acceptable for a particular sequence?"
Interviewer guidance: The candidate should know that noncontinuous sequences can skip numbers by design (e.g., due to rolled-back transactions or preallocated numbers not used) and that this is usually acceptable. They might mention that for continuous sequences, F&O can recycle unused numbers (no gaps) but they come with overhead and require occasional cleanup jobs. If strict sequence continuity is required, switching to a continuous sequence (and possibly leveraging newer performance improvements or scheduling cleanup processes) is necessary, but otherwise, gaps can be tolerated.