In caching, what does TTL define?

In caching, what does TTL define?

• A. The maximum number of items the cache can hold.
• B. The order in which items are evicted from the cache.
• C. The duration data remains valid before it's considered stale.
• D. The time it takes to fetch data from the origin on cache miss.

Answer: (C)

TTL, or Time To Live, defines how long cached data stays considered fresh before it’s treated as stale. It sets the expiration window for a cached item, after which the cache will typically revalidate or fetch an updated copy from the origin. This is about data validity and freshness, not about how much you can cache, the order in which items are evicted, or how long a fetch takes on a miss. For example, with a TTL of 5 minutes, you can serve that item from the cache for five minutes before deciding whether to revalidate or retrieve a fresh copy.

TTL, or Time To Live, defines how long cached data stays considered fresh before it’s treated as stale. It sets the expiration window for a cached item, after which the cache will typically revalidate or fetch an updated copy from the origin. This is about data validity and freshness, not about how much you can cache, the order in which items are evicted, or how long a fetch takes on a miss. For example, with a TTL of 5 minutes, you can serve that item from the cache for five minutes before deciding whether to revalidate or retrieve a fresh copy.