If the CACHE option is set, then the size of the cache must be at least 100 to ensure efficient usage and avoid performance issues. Their usage will always have a performance impact on the primary database, as any interaction with the sequences requires processing power. Their usage may have a performance impact on the physical standby database if the CACHE size is too small, as a small cache size necessitates more frequent trips to the primary database to retrieve sequence values, resulting in overhead and latency.