The Performance Of A Multiversion Access Method

Abstract

The <i>Time-Split B-tree</i> is an integrated index structure for a versioned timestamped database. It gradually migrates data from a current database to an historical database, records migrating when nodes split. Records valid at the split time are placed in both an historical node and a current node. This implies some redundancy. Using both analysis and simulation, we characterise the amount of redundancy, the space utilization, and the record addition (insert or update) performance for a spectrum of different rates of insertion versus update. Three splitting policies are studied which alter the conditions under which either time splits or key space splits are performed.