Redis 是一个高性能的key-value数据库。Redis 的出现，很大程度补偿了memcached这类keyvalue存储的不足，在部分场合可以对关系数据库起到很好的补充作用。它提供了Python，Ruby，Erlang，PHP客户端，使用很方便。

Redis 4.0 Rc3 包括许多 bug 修复和功能改进，建议使用 4.0 RC2 的用户尽快升。值得注意的变化：

• Finally the infamous leakage of keys with an expire, in slaves that are configured as writable, is fixed. 

• A serious MIGRATE issue forgetting to store the TTL of the key under certain conditions is fixed. 

• An in-depth investigation of the ziplist implementation was performed. 

• Refactoring and function to dump a ziplist for debugging purposes

• New major feature: Memory de-fragmentation. This feature, contributed by Oran Agra, allows Redis to perform "online defragmentation" of memory if the Jemalloc allocator is used. There is some documentation in the example `redis.conf` file. 

• Support for ARM. 

• Fix a very important "family of bugs" about PSYNC2, thanks to the help of Kevin McGehee, Siran Yang and Oran Agra.

• Hash function moved to SipHash 1-2 variant. 

• Redis Cluster failure detection improved in different ways, the most important result is to exchange a lot less messages among nodes. 

完整更新内容

下载地址：

• Source code (zip)

• Source code (tar.gz)