A primitive sequence that would always use an index to access the next element would incur the cost for walking the tree at every access.

一个原生的sequence使用索引访问下一个元素，这样可能导致每次访问的时候都需要遍历树。

youdao

Due to the data access skew, index technology based on data access probability is proposed. At last ord algorithm is proposed to create optimal broadcast sequence according to given index tree.

针对数据库中数据访问的倾斜性，文章提出建立基于数据访问概率的索引技术，并给出了ORD算法，它可以根据给定的索引树创建最优的广播序列。

youdao