分库分表全局主键生成策略

1.系统生成策略，参照twitter的snowflake算法。

  算法参照 http://blog.youkuaiyun.com/coffee_hc/article/details/49071817
  代码: https://github.com/coffeehc/cfsequence  http://www.cnblogs.com/relucent/p/4955340.html

2.使用数据库自增的策略生成主键。参照 http://blog.youkuaiyun.com/bluishglc/article/details/7710738

更多参照: http://mp.weixin.qq.com/s?__biz=MzIxNjA5MTM2MA==&mid=403794436&idx=1&sn=3554136143364afba331dbfe543ceb6f&scene=0#wechat_redirect