To keep a hot key from expiring under load, a reader can refresh it at random shortly before its TTL ends, more likely the closer expiry is. This is blank.

Answer

To keep a hot key from expiring under load, a reader can refresh it at random shortly before its TTL ends, more likely the closer expiry is. This is probabilistic early expiration.

Also accepted: probabilistic early recomputation, early recomputation, XFetch for probabilistic early expiration.

Why

Because only an occasional reader refreshes early, the key is rebuilt once instead of by thousands of readers at the moment it expires, without any lock.

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