The main purpose of this work is to extend the processing capabilities of the optimizer of a relational DBMS in order to effectively include the treatment of disjunctive queries. To this aim two new strategies are presented, whose main features are based on the application of splitting techniques during the execution of the join operations. Their effectiveness is first shown by means of an example; then some comparisons with standard procedures are made, showing promising results. The inclusion of these techniques in the relational query processing environment requires a broader view of the evaluation phase, where more than one expression can now be present. A heuristic algorithm for the reduction of the number of candidate relational expressions is also proposed. © 1989 IEEE
Ciaccia P., Scalas M.R. (1989). Optimization Strategies for Relational Disjunctive Queries. IEEE TRANSACTIONS ON SOFTWARE ENGINEERING, 15(10), 1217-1235 [10.1109/TSE.1989.559773].
Optimization Strategies for Relational Disjunctive Queries
Ciaccia P.;Scalas M. R.
1989
Abstract
The main purpose of this work is to extend the processing capabilities of the optimizer of a relational DBMS in order to effectively include the treatment of disjunctive queries. To this aim two new strategies are presented, whose main features are based on the application of splitting techniques during the execution of the join operations. Their effectiveness is first shown by means of an example; then some comparisons with standard procedures are made, showing promising results. The inclusion of these techniques in the relational query processing environment requires a broader view of the evaluation phase, where more than one expression can now be present. A heuristic algorithm for the reduction of the number of candidate relational expressions is also proposed. © 1989 IEEEI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
