The difference between redis cache breakdown and cache penetration

The difference between cache breakdown and cache penetration: Cache breakdown: occurs when a large number of concurrent requests access uncached keys, causing excessive pressure on the database. Cache penetration: occurs when malicious requests or crawlers frequently access keys that have never been cached, resulting in unnecessary database access.

The difference between Redis cache penetration and cache penetration

Question: Cache penetration What is the difference between penetration and cache penetration?

Answer:

Cache penetration and Cache penetration are two different cache problems:

Cache breakdown

• Description: When a specific key does not exist in the cache, and there are a large number of concurrent requests accessing it at the same time in a short period of time When this key is entered, a cache breakdown occurs.
• Cause: Because the key is not in the cache, all requests directly access the database, resulting in excessive pressure on the database and even a crash.
• Solution: Use a locking mechanism or other means to prevent concurrent requests from accessing uncached keys at the same time, and handle cache misses.

Cache Penetration

• Description: When certain keys have never been cached and are accessed through malicious requests or Cache penetration occurs when crawlers access frequently.
• Cause: The key does not exist in the cache, all requests will directly access the database, even if the key does not exist.
• Solution: Check the validity of all requests, and directly return errors or null values ​​for non-existent keys to avoid unnecessary database access.

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