*Total -- 56.62kb -> 24.34kb (57.01%)

/images/database-id-sequence-step.png -- 28.31kb -> 12.17kb (57.01%)
/docs/high-concurrency/images/database-id-sequence-step.png -- 28.31kb -> 12.17kb (57.01%)

更新分库分表后如何生成唯一ID