Concurrent file reorganization for record clustering: a performance study

The authors presents performance analysis of a concurrent file reorganization algorithm. They examined the effect of buffer size, degree of reorganization, and write probability of transactions on system throughput. The problem of file reorganization considered involves altering the placement of records on pages on a secondary storage device. This reorganization must be done in-place. The approach is appropriate for a non-in-place reorganization. The motivation for such a physical change is to improve the database system´s performance, by minimizing the number of page accesses made in answering a set of queries. It is shown through simulation that the algorithm, when run concurrently with user transactions, provides an acceptable level of overall database system performance