内存映射数据库

Question

I have 8 terabytes of data composed of ~5000 arrays of small sized elements (under a hundred bytes per element). I need to load sections of these arrays (a few dozen megs at a time) into memory to use in an algorithm as quickly as possible. Are memory mapped files right for this use, and if not what else should I use?

Answer 1

Given your requirements I would definitely go with memory mapped files. It's almost exactly what they were made for. And since memory mapped files consume few physical resources, your extremely large files will have little impact on the system as compared to other methods, especially since smaller views can be mapped into the address space just before performing I/O (eg, those arrays of elements). The other big benefit is they give you the simplest working environment possible. You can (mostly) just view your data as a large memory address space and let Windows worry about the I/O. Obviously, you'll need to build in locking mechanisms to handle multiple threads, but I'm sure you know that.