Redis 事务

127.0.0.1:6379> WATCH key//监视key
OK
127.0.0.1:6379> MULTI//开启一个事务块
OK
127.0.0.1:6379> set key 1//do something
QUEUED
127.0.0.1:6379> get key//do something
QUEUED
127.0.0.1:6379> EXEC//执行
1) OK
2) "1"
127.0.0.1:6379> 

127.0.0.1:6379> get key
"1"
127.0.0.1:6379> MULTI
OK
127.0.0.1:6379> set key 2
QUEUED
127.0.0.1:6379> DISCARD//取消事务
OK
127.0.0.1:6379> get key//key值不变
"1"
127.0.0.1:6379> 

127.0.0.1:6379> get key
"1"
127.0.0.1:6379> WATCH key//监视key
OK
127.0.0.1:6379> set key 2//开启事务之前修改key值
OK
127.0.0.1:6379> MULTI
OK
127.0.0.1:6379> set key 3
QUEUED
127.0.0.1:6379> get key
QUEUED
127.0.0.1:6379> EXEC//执行失败,是因为监视了key,key在执行事务之前被改动了
(nil)    
127.0.0.1:6379>