Redis 红锁超时引发的灾难（redis 锁获取超时）
Recent years have witnessed the remarkable success of redis in the development of distributed applications. Redis is a rich set of data structures and powerful functions, which provides strong support for applications such as message queuing and cache storage. It is not only faster in storage performance but also more convenient in development.
However, in the process of using redis, especially when the number of concurrent users is large, some operations may be blocked due to busy resources, which results in an unusually long timeout. This is a typical redis deadlock problem we often call redis lock.
When the redis lock timeout is too long, it will inevitably cause serious problems to the application system. For example, a concurrent writing operation times out, leading to the flure of the original task. Or the cache timeout is too long, leading to a large amount of data being fetched from the database every time, which affects the response time of the application interface.
Fortunately, redis provides multiple sets of locks for solving the timeout deadlock. For example, through the setex command, we can write in the form of name-value prs to redis. At the same time, when writing, we can set a timeout to the key. When the key time expired, the write operation would fl automatically and the read operation would fl automatically because the key does not exist.
In addition, when using redis locks, it is necessary to set a reasonable timeout value.Writing too long can cause inefficient reading and writing, resulting in unnecessary overhead; too short and it is likely to cause data consistency problems, thus increasing errors.
In short, lock is an important part of distributed application redis, reasonable use of the lock can greatly enhance the performance of distributed applications, but improper use of redis locks can cause disasters. Therefore, when using redis locks, you must pay attention to the reasonable setting of lock timeout to ensure the stability and reliability of redis applications.
