在Redis.conf中，介绍了各种关键的驱逐策略，并介绍了它们的工作原理。
我相信我想使用volatile-ttl，但我找不到有关它如何运作的充分信息。
在脸上，很明显;最近到期时间的密钥首先出现。如果Redis在过期时间内驱逐所有键怎么办？如果它仍然需要继续驱逐以保持在maxmemory之下，它接下来选择什么呢？
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached. You can select among five behaviors:
#
# volatile-lru -> remove the key with an expire set using an LRU algorithm
# allkeys-lru -> remove any key according to the LRU algorithm
# volatile-random -> remove a random key 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 expire at all, just return an error on write operations
答案 0 :(得分：1)
volatile-ttl策略将根据其TTL按升序排除所有易失性密钥（意味着密钥设置为过期）。当没有剩下更多易失性密钥时 - 即所有剩余的密钥都是非易失性的 - 并且假设RAM压力继续，将不再进一步驱逐，Redis将回复OOM（内存不足）错误。
答案 1 :(得分：1)
会抛出内存不足错误
127.0.0.1:6379[2]> info memory
# Memory
used_memory:2091560
used_memory_human:1.99M
used_memory_rss:4022272
used_memory_rss_human:3.84M
used_memory_peak:2097296
used_memory_peak_human:2.00M
total_system_memory:16712204288
total_system_memory_human:15.56G
used_memory_lua:37888
used_memory_lua_human:37.00K
maxmemory:2097152
maxmemory_human:2.00M
maxmemory_policy:volatile-lru
mem_fragmentation_ratio:1.92
mem_allocator:libc
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(error) OOM command not allowed when used memory > 'maxmemory'.