Query pre-execution and batching in Paradise: a two-pronged approach to the efficient processing of queries on tape-resident raster images

Abstract

The focus of the Paradise project (D. DeWitt et al., 194; J. Patel et al., 1997) is to design and implement a scalable database system capable of storing and processing massive data sets such as those produced by NASA's EOSDIS project. The paper describes extensions to Paradise to handle the execution of queries involving collections of satellite images stored on tertiary storage. Several modifications were made to Paradise in order to make the execution of such queries both transparent to the user and efficient. First, the Paradise storage engine (the SHORE storage manager) was extended to support tertiary storage using a log structured organization for tape volumes. Second, the Paradise query processing engine was modified to incorporate a number of novel mechanisms including query pre execution, object abstraction, cache conscious tape scheduling, and query batching. A performance evaluation on a working prototype demonstrates that, together, these techniques can provide a dramatic improvement over more traditional approaches to the management of data stored on tape.