research issues in next generation dbms for mobile platforms
Recently, flash memory(in particular, NAND) is being rapidly deployed as data storage for mobile platforms such as PDAs, MP3 players, mobile phones and digital cameras, mainly because of its many advantages over its competitor, hard disk, including its low electronic power, non-volatile storage, high performance, physical stability, smaller size, light weight, and portability. Considering its rapid technical improvement both in capacity and speed, it will have a competitive advantage over its rivalry minidrive (i.e. a small size hard disk) under 100 Gbytes within a few years, As the applications in next generation mobile platforms become large, complex, and more data-oriented, they requires the database technology, because the file interface is too complex to manage their complicated data requirements. However, flash memory, compared to hard disk, has a few unique characteristics, and thus the traditional disk-based database technology does not seem to go well with flash memory. Therefore, we need to revisit almost every aspect of DBMS implementation techniques from the perspectives of flash memory. In this paper, we introduce the technical characteristics of flash memory, which we think might have huge impact on database performance to database community that are 1) no-overwrite (erase-before-write paradigm), 2) asymmetric read and write speed, and 3) no seek or rotation time. These small differences necessitate us to revisit all the major DBMS modules which have evolved over the several decades. Based on the characteristics, we identify several key issues in implementing major DBMS modules, and suggest alternative approaches to solve the issues. The topics covered in this article are neither comprehensive nor in-depth, but the main goal of this article is just to issue that a practical and urgent research topic is ahead and it poses us many challenges and opportunities.
mobile platforms flash-memory database