N. Bassiliades et I. Vlahavas, HIERARCHICAL QUERY EXECUTION IN A PARALLEL OBJECT-ORIENTED DATABASE SYSTEM, Parallel computing, 22(7), 1996, pp. 1017-1048
Citations number
17
Categorie Soggetti
Computer Sciences","Computer Science Theory & Methods
We present a hierarchical query execution strategy for a parallel obje
ct-oriented database (OODB) system. The system, named PRACTIC, is base
d on a concurrent active class management model and is mapped to an ab
stract hierarchical multiprocessor architecture. The proposed strategy
is studied analytically and by simulation on a transputer-based machi
ne, verifying the theoretical results. Although the analysis suits bot
h main-memory and disk-based database systems, it becomes significant
for main-memory systems where the multiprocessor initialization and co
mmunication overheads are comparable to the actual workload. The hiera
rchical query execution strategy is proved much better than the usual
flat strategy of parallel database systems, except some clearly identi
fied extreme cases, where flat processing is better. Furthermore, we p
ropose a declustering scheme for space optimization to improve process
or utilization and single-class query performance, by having different
classes share memory and computation power of neighboring processing
elements.