Glossary · Phase 11 · Professional practice
Cache stampede
Many requests missing the cache at once, such as when a popular entry expires, and all hitting the database.
Try it now
The second "a" is a hit, so it moves to the newest end. When "c" arrives, "b" is the least recently used and is evicted.
Learn it properly
Caches, queues and background jobs · Speed reads with caches, and move slow work to queues that retry safely. About 40 minutes.
Other terms from the same lesson
- at-least-once delivery: A guarantee that each message is delivered, but possibly more than once, so consumers must be idempotent.
- cache-aside: Read the cache first; on a miss, load from the source, store the result in the cache, and return it.
- dead-letter queue: Where a queue puts jobs that failed too many times, so a person can inspect them.
- visibility timeout: How long a pulled job stays hidden from other workers. If it isn't acknowledged in time, it's retried.
Never trained an AI?
Teach a small one to write, right in your browser. It takes about 20 seconds and needs no account.