Redis expiration elimination mechanism

Delete regularly ---> Lazy deletion ---> Delete periodically

For periodic deletion, there are 8 A data culling strategy

LRU Algorithm （ Recently at least use ）

volatile-lru： Select the least recently used data from the data set with expiration time set

allkeys-lru： Remove the least recently used... When memory is insufficient for new write data key

LFU Algorithm （ The frequency of use is the least ）

volatile-lfu： Select the data with the least frequency of use from the data set with expiration time

allkeys-lfu： When the memory is insufficient to accommodate the newly written data, remove the least frequently used key

allkeys-random： Choose data elimination from data set

volatile-random： Select any data elimination from the data set with expiration time set

volatile-ttl： Select the data that will expire from the data set with expiration time set

no-enviction： When the memory is not enough to hold the newly written data , Error will be reported in new write operation