Main-Memory Management in Temporal Object Database Systems

In this paper, we describe main-memory management and the most important buffers in the Vagabond server, a transaction-time temporal object database system currently under development at the Norwegian University of Science and Technology. Special emphasis is given to fine granularity buffering of OID index entries and objects. In order to make it easier for the system to adaptively change the size of the buffers with different access patterns and workload, buffer models will be used to decide the buffer sizes. In this paper, we present an adoption of a buffer model by Bhide, Dan and Dias. By comparing simulations with the analytical model, we have shown that in most cases, the deviations between the model and the simulations are acceptable even in the case of a mixed workload with both read and write accesses, where items are locked in the buffer until they are installed into the index or database.