基于NOR Flash实现KV数据库的应用研究

为在水文自动测报系统遥测站的遥测终端机中基于NOR Flash存储器可靠地存放系统运行参数,分析遥测终端机中常用固态存储器的读写特点和KV键值数据库的实现方式,设计一种基于W25Q256存储器实现KV键值数据库的解决方案.方案充分应用NOR Flash存储器的读写特点,针对同一个地址重复写入的最小编程颗粒度为1 bit,结合KV键值实现一个键值对状态的顺序变化,进而通过在存储器的一段空间内顺序增加地址存放KV键值对,实现KV键值对的新增、修改、删除和检索操作,达到磨损均衡和异常掉电恢复效果.在嵌入式系统中,相较于常用的采用固定地址保存运行参数的方案,该研究方案能有效延长NOR Flash存储器的使用寿命,提高系统的稳定可靠性.

Application Research of KV database based on NOR Flash

In order to reliably store the system operating parameters based on NOR Flash memory in remote telemetry unit (RTU) of telemetry station of hydrological automatic measurement and reporting system and analyze the implementation mode of common Key-value database and the reading and writing characteristics of common solidstate memory in telemetry terminal, the solution to realize KV database based on W25Q256 memorizer is designed. Aiming at the minimum programming granularity of repeated writing at the same address is 1bit, the scheme makes full use of the reading and writing characteristics of NOR Flash memory, realizes sequential change of KV pair states by combining with the Key-Value pairs, and store the KV pair by sequentially adding an address in a section of memory space to realize the sequential cyclic addition, modification, deletion and retrieval of KV pairs. In embedded system, this research scheme can effectively prolong the service life of NOR flash memory and improve the stability and reliability of the system, compared with the common scheme of using fixed address to save operating parameters.