negative caching

RU: негативное кеширование

Storing the fact that a lookup produced no result, so subsequent identical queries are answered from cache without hitting the origin. Most prominent in DNS (RFC 2308): NXDOMAIN and NODATA responses are cached for the lesser of the SOA record's own TTL and its MINIMUM field (per RFC 2308). The same principle applies to application caches — caching a 404 or empty database result prevents repeated expensive lookups for non-existent keys.