Redis 3.2.1 发布了，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。
- A critical bug in Sentinel was hopefully fixed. During the big 3.2
refactoring of Redis Sentinel, in order to implement connection sharing
to make Sentinel able to scale better (few Sentinels to monitor many
masters), a bug was introduced that mis-counted the number of pending
commands in the Redis link. This in turn resulted into an inability to talk
with certain Redis instances. A common result of this bug was the inability
of Redis Sentinel to reconfigure back the old master, after a failover,
when it is reachable again, as the slave of the new master. This was due
to the inability to talk with the old master at all.
2. BITFIELD bugs fixed.
3. GEO commands fixes on syntax errors and edge cases.
4. RESTORE now accepts dumps generated by older Redis versions.
5. Jemalloc now is really configured to save you memory, for a problem a
change in the jemalloc configuration did not really survived when the
3.2.0 release was finalized.
6. TTL and TYPE command no longer alter the last access time of a key, for
LRU evictions purposes. A new TOUCH command was introduced *just* to
update the access time of a key.
7. A bug was fixed in redis-cli, that connected to the instance running on the
port 6379 if there was one, regardless of what was specified.
8. TCP keep alive is now enabled by default. This should fix most ghost
connections problems without resulting in any practical change in otherwise
9. A Sentinel crash that could happen during failovers was fixed.