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Explain Redlock in Depth
Previously, I introduced two types of locks, mutex locks and barriers, and I used Redis as an example to explain the differences between the two types of locks. Shortly after that, I received a reply saying that if you want to implement distributed locks, the Redis approach is not enough and you should refer to Redlock.
Well, his opinion is basically right.
Although Redlock is implemented through Redis, it can achieve a very high level of consistency and is one of the best paradigms for implementing distributed locking. However, Redlock has a very high cost behind it and is not suitable for all organizations and services.
Nevertheless, I will introduce Redlock and present my thoughts on why Redlock is impractical.
Redis is not reliable
Before getting started, I should emphasize that Redis persistence is unreliable, even with the most strict settings.
However, in a cluster environment, a Master may have a number of Slave redundancies. Is Redis still unreliable under these conditions? The answer is yes.
In Redis implementation, data replication is performed by the background process, not the master thread, so when a client writes successfully, it does not mean the data is replicated successfully. One of the procedures leading to the…
