找到redis的配置文件,搜索The default is
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory # is reached. You can select among five behaviors: # # volatile-lru -> Evict using approximated LRU among the keys with an expire set. # allkeys-lru -> Evict any key using approximated LRU. # volatile-lfu -> Evict using approximated LFU among the keys with an expire set. # allkeys-lfu -> Evict any key using approximated LFU. # volatile-random -> Remove a random key among the ones with an expire set. # allkeys-random -> Remove a random key, any key. # volatile-ttl -> Remove the key with the nearest expire time (minor TTL) # noeviction -> Don't evict anything, just return an error on write operations. # # LRU means Least Recently Used # LFU means Least Frequently Used # # Both LRU, LFU and volatile-ttl are implemented using approximated # randomized algorithms. # # Note: with any of the above policies, Redis will return an error on write # operations, when there are no suitable keys for eviction. # # At the date of writing these commands are: set setnx setex append # incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd # sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby # zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby # getset mset msetnx exec sort # # The default is: # # maxmemory-policy noeviction
上述可知默认的淘汰策略为noeviction
而可供选择的淘汰策略有8种
在设置了过期时间的键空间中，优先移除最近未使用的key
allkeys-lru
在所有主键空间中，优先移除最近未使用的key
volatile-lfu
在设置了过期时间的键空间中，将访问频率最少的键值对淘汰
allkeys-lfu
在所有主键空间中，将访问频率最少的键值对淘汰
volatile-random
在设置了过期时间的键空间中，随机移除某个key
allkeys-random
在所有主键空间中，随机移除某个key
volatile-ttl
从已设置过期时间的数据集中挑选将要过期的数据淘汰
noeviction
如果缓存数据超过了maxmemory限定值，并且客户端正在执行的命令(大部分的写入指令，但DEL和几个指令例外)会导致内存分配，则向客户端返回错误响应
其中volatile-lfu 和 allkeys-lfu是Redis 4.0新引入的策略,根据自己的需要自行设置