What are cache penetration, cache breakdown, and cache avalanche

Stored in cache ⼤ Most of them are hot data ,⽬ The key is to prevent ⽌ Requests can get data directly from the cache ,⽽ No ⽤ visit Mysql.

• Cache avalanche ： If something in the cache ⼀ moment ⼤ Batch hotspot data expires at the same time , That could lead to ⼤ Volume request direct access Mysql 了 , The solution is to increase the expiration time ⼀ Point random value , In addition, if you build ⼀ individual ⾼ can ⽤ Of Redis Clustering is also anti ⽌ slow Save avalanche effectively ⼿ paragraph
• Cache breakdown ： Similar to cache avalanche , Cache avalanche is ⼤ Batch hotspot data is invalid ,⽽ Cache breakdown is Refer to ⼀ Hot spots key Sudden failure , It also led to ⼤ Volume request direct access Mysql database , This is cache breakdown , solve ⽅ The case is to consider this hot spot key No Set the expiration time
• Cache penetration ： If ⼀ Always visit redis Of ⼤ The amount key All in redis Does not exist in the （ For example, hackers deliberately forge ⼀ Something messy key）, It will also put pressure on the data ⼒, This is cache penetration , solve ⽅ Case is to make ⽤ The bloon filter , Its work ⽤ Namely If it thinks ⼀ individual key non-existent , So this key There is no certainty that there is , So you can add ⼀ Layer bron filter comes Intercept what doesn't exist key