一种具有自适应机制的闪存数据库索引结构

针对闪存数据库系统索引技术中基于日志更新策略存在的检索效率低、日志空间分配不合理及合并带来的高昂更新代价等问题，提出一种具有自适应机制的索引结构LM-B+TREE。LM-B+TREE将索引的更新缓冲页映射于传统B+TREE的相应节点,并根据闪存索引的读写负载及读写代价差异，动态地分配缓冲更新区，自适应地调整索引架构。实验证明LM-B+TREE能够动态地调整索引架构来适应索引的读写负载代价，在减少索引更新代价的同时，有效地提高了索引的查询性能。

Index structure with self-adaptive mechanism in flash-based database system

The log-based index update mechanism in flash-based database system has following shortage: low query efficiency, expensive update cost, unreasonable space allocation and merge for the log. In order to solve these problems, a new adaptive index structure named LM-B+TREE was proposed. LM-B+TREE can map the page for index update buffer into corresponding node of traditional B+ TREE. Furthermore, according to the read/write workload and read/write overhead, LM-B+TREE can dynamically maintain the update buffer and adjust the index frame adaptively. The experimental results show that LM-B+ TREE can dynamically adjust the index structure to adapt to the read-write workload, significantly reduce the overhead of index update and improve the query performance.