[PingCAP docs, Error Codes and Troubleshooting]: Check the TiKV status, monitoring data and logs to find the hotspot: unbalanced regions, too many concurrent scans, or disk IO saturation. Reduce the concurrent client count or split the hot transaction, and retry with backoff since this is transient. If it recurs at steady load, the fix is more TiKV capacity, not more retries.

Context: Queries to TiDB Cloud fail with ERROR 9003 (HY000): TiKV Server is Busy. This occurs when the TiKV workload is too high to keep up with incoming requests.