Backend & systems·Caching and invalidation
you cache the fact that the thing does not exist, so a bad id cannot hit the database on every single retry.
Negative caching
Storing a marker for a miss so that repeated lookups of an absent key are served from cache. Without it, any key that never resolves is a permanent cache bypass, which is both a performance problem and an easy denial-of-service vector. Keep the negative TTL short, or a newly created record stays invisible for as long as the marker lives.