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Cluster cluster addslots(集群 槽位) cluster count failure reports(集群计数失败报告) cluster countkeysinslot cluster delslots cluster failover cluster forget cluster getkeysinslot cluster info cluster keyslot(集群键槽) cluster meet cluster nodes(集群节点) cluster replicate(集群复制) cluster reset(集群重置) cluster saveconfig cluster set config epoch cluster setslot cluster slaves cluster slots readonly readwrite Connection auth echo ping quit select swapdb Geo geoadd geodist geohash geopos georadius georadiusbymember Hashes hdel hexists hget hgetall hincrby hincrbyfloat hkeys hlen hmget hmset hscan hset hsetnx hstrlen hvals HyperLogLog pfadd pfcount pfmerge Keys del dump exists expire expireat keys migrate move object persist pexpire pexpireat pttl randomkey rename renamenx restore scan sort touch ttl type unlink wait Lists blpop brpop brpoplpush lindex linsert llen lpop lpush lpushx lrange lrem lset ltrim rpop rpoplpush rpush rpushx Pub/Sub psubscribe publish pubsub punsubscribe subscribe unsubscribe Scripting eval evalsha script debug script exists script flush script kill script load Server bgrewriteaof bgsave client getname client kill client list client pause client reply client setname command command count command getkeys command info config get config resetstat config rewrite config set dbsize debug object debug segfault flushall flushdb info lastsave monitor role save shutdown slaveof slowlog time Sets sadd scard sdiff sdiffstore sinter sinterstore sismember smembers smove spop srandmember srem sscan sunion sunionstore Sorted Sets zadd zcard zcount zincrby zinterstore zlexcount zrange zrangebylex zrangebyscore zrank zrem zremrangebylex zremrangebyrank zremrangebyscore zrevrange zrevrangebylex zrevrangebyscore zrevrank zscan zscore zunionstore Strings append bitcount bitfield bitop bitpos decr decrby get getbit getrange getset incr incrby incrbyfloat mget mset msetnx psetex set setbit setex setnx setrange strlen Transactions discard exec multi unwatch watch
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GETSET key value

自1.0.0起可用。

时间复杂度: O(1)

以原子方式设置keyvalue,并返回存储在旧值keykey存在但返回一个错误,但不包含字符串值。

设计模式

GETSET 可以与 INCR 一起用于计数原子重置。例如:mycounter每次某个事件发生时,一个进程可能会调用 INCR 来对付该键,但是我们需要不时地获取该计数器的值并将其重置为零。这可以使用GETSET mycounter "0"

redis>  INCR mycounter (integer) 1 redis>  GETSET mycounter "0" "1" redis>  GET mycounter "0"

返回值

散装字符串回复:旧值存储在key,或者nilkey不存在。

例子

redis>  SET mykey "Hello" "OK" redis>  GETSET mykey "World" "Hello" redis>  GET mykey "World"

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