Algorithms for PCM-Database Operators
Abhimanyu Singh · 2013
Phase change memory (PCM) is an emerging memory technology. It has many interesting properties. It is random access, byte-addressable and non-volatile memory. PCM has 2-4× density than DRAM. Its idle power consumption is less than that of DRAM. PCM read latency is comparable to DRAM. But its write latency is high and we can perform only limited number of writes to a PCM cell (10−10). If we compare PCM with NANDFlash then PCM has much better endurance and read/write latency than NAND-Flash. Because of all these characteristics it is expected that PCM will become one of the main components in the memory hierarchy in computer systems. A design goal of databases for such computer systems would be to reduce writes to PCM without compromising much on running time. We should reduce writes because if writes to PCM will be more then it will wear out quickly and the system will not be usable at all. Running time is also important because user can’t wait forever for the result of any processing task. We did background study of work done for systems having PCM and designed new PCM-aware algorithms for two database operators, sort and join.