The vagabond temporal OID index: an index structure for OID indexing in temporal object database systems

In an object database system using logical OIDs, an OID index (OIDX) is necessary to map from logical OID to the physical location of an object. In a temporal object database system (TODB), this OIDX also contains the timestamps of the object versions. OIDX maintenance can be very costly, and can easy become the bottleneck of such a system. The main reason for this, is that in a TODB the OIDX needs to be updated every time an object is updated. In order to reduce the access costs, a new index structure, particularly suitable to TODB requirements, is necessary. In this paper, we describe an OIDX for TODBs, the Vagabond Temporal OID Index (VTOIDX). The main goals of the VTOIDX are: 1) support for temporal data, while still having index performance close to a non-temporal (one-version) database system, 2) efficient object-relational operation, and 3) flexible tertiary storage migration of partitions of the index. In this paper, we describe the physical organization and the operations of the VTOIDX