不考虑成本的存储重新分配
Cost-oblivious storage reallocation
摘要：
数据库需要分配和释放磁盘上的存储块。释放的块会在没有数据存储的地方引入洞。分配系统试图重用这些释放的区域，以便最小化磁盘上的占用空间。如果先前分配的块不能被移动，则该问题被称为内存分配问题，已知该问题在占用空间中具有对数开销。本文定义了存储重新分配问题，以前分配的块可以移动，或重新分配，但在一定的成本。这里提出的算法是成本无关的，因为它们适用于广泛而合理的成本函数类，即使它们不知道成本函数是什么。目标是最小化存储占用空间，即包含已分配对象的最大内存地址，同时最小化重新分配成本。本文给出了一种渐进最优的存储再分配算法，该算法的存储占用最多为（1+ 1/2）倍最优，再分配费用最多为原分配费用的（1/1/2）倍，也是最优的.只要分配/再分配成本函数是次加性的，算法是成本无关的。
英文摘要：
Databases need to allocate and free blocks of storage on disk. Freed blocks introduce holes where no data is stored. Allocation systems attempt to reuse such deallocated regions in order to minimize the footprint on disk. If previously allocated blocks cannot be moved, the problem is called the memory allocation problem, which is known to have a logarithmic overhead in the footprint. This paper defines the storage reallocation problem, where previously allocated blocks can be moved, or reallocated, but at some cost. The algorithms presented here are cost oblivious, in that they work for a broad and reasonable class of cost functions, even when they do not know what the cost function is. The objective is to minimize the storage footprint, that is, the largest memory address containing an allocated object, while simultaneously minimizing the reallocation costs. This paper gives asymptotically optimal algorithms for storage reallocation, in which the storage footprint is at most (1+epsilon) times optimal, and the reallocation cost is at most (1/epsilon) times the original allocation cost, which is also optimal. The algorithms are cost oblivious as long as the allocation/reallocation cost function is subadditive.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
