In shared-disk database systems, disk access has to be scheduled properly to avoid unnecessary contention between processors. The first part of this report studies the allocation of intermediate results of join queries (buckets) on disk and derives heuristics to determine the number of processing nodes and disks to employ. Using an analytical model, we show that declustering should be applied e...

For complex queries in parallel database systems, substantial amounts of data must be redistributed between operators executed on different processing nodes. Frequently, such intermediate results cannot be held in main memory and must be stored on disk. To limit the ensuing performance penalty, a data allocation must be found that supports parallel I/O to the greatest possible extent. In this p...

Scientiic databases must be able to eeciently run subset retrievals of multi-dimensional data sets. If the data sets are very large signiicant retrieval speedups can be obtained via parallelism. In this paper we present a new parallel distributed shared nothing Rtree architecture. To the best of our knowledge this is the rst signiicant experimental study demonstrating practical application of p...

Declustered data organizations in disk arrays (RAIDs) achieve less-intrusive reconstruction of data after a disk failure. We present PDDL, a new data layout for declustered disk arrays. PDDL layouts exist for a large variety of disk array configurations with a distributed spare disk. PDDL declustered disk arrays have excellent run-time performance under light and heavy workloads. PDDL maximizes...

Magnetic disk capacities have grown over the last decades by a factor of at least ten thousand. While the minicomputer disk drives of the late eighties could only store 600 MB of data [5], 8TB or 10TB disk drives are common today. The same is not true for disk transfer rates: they are just one hundred times higher than those of the late eighties. As a result, copying the entire contents of a di...

Euro-Par Topic 5 addresses data management issues in parallel and distributed computing. Advances in data management (storage, access, querying, retrieval, mining) are inherent to current and future information systems. Today, accessing large volumes of information is a reality: Data-intensive applications enable huge user communities to transparently access multiple pre-existing autonomous, di...

A b s t r a c t. We present a technique to decluster a spatial access method on a shared-nothing multi-computer architecture [DGS + 90]. We propose a software architecture with the R-tree as the underlying spatial access method, with its non-leaf levels on the 'master-server' and its leaf nodes distributed across the servers. The major contribution of our work is the study of the optimal capaci...

Thomas J.E. Schwarz, S.J. and Walter A. Burkhard Gemini Storage Systems Laboratory, University of California at San Diego Abstract|We de ne and analyze the ACATS declustering scheme for use with the classic Level 5 as well as MDS RAIDs. ACATS provides a paradigm for distributed sparing and checking as well. Using Markov models we calculate the reliability of classic Level 5 as well as MDSRAIDs ...