منابع مشابه
Optimization of Queries with User
Relational databases provide the ability to store user-deened functions and predicates which can be invoked in SQL queries. When evaluation of a user-deened predicate is relatively expensive, the traditional methods of evaluating predicates as early as possible is no longer a sound heuristic. There are two previous approaches for optimizing such queries. However, none of these approaches is abl...
متن کاملOptimization of Queries with User-deened Predicates
Relational databases provide the ability to store user-de ned functions and predicates which can be invoked in SQL queries. When evaluation of a user-de ned predicate is relatively expensive, the traditional method of evaluating predicates as early as possible is no longer a sound heuristic. There are two previous approaches for optimizing such queries. However, none of these approaches is able...
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The early grouping technique is a new method for optimizing aggregate queries. It provides more opportunities for the query optimizers to find optimal plans because all possible placements of the GROUP BY operators in the query trees are considered during the optimization process. Howeve1; to employ this technique, one of the requirements is that the aggregate function in the query must be dist...
متن کاملOptimization of bound disjunctive queries with constraints
This paper presents a technique for the optimization of bound queries over disjunctive deductive databases with constraints. The proposed approach is an extension of the wellknown Magic-Set technique and is well-suited for being integrated in current bottom-up (stable) model inference engines. More specifically, it is based on the exploitation of binding propagation techniques which reduce the ...
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We propose an algorithm for pushing min and max aggregates into recursive predicates, while preserving query equivalence under certain monotonicity constraints. The transformed query is often safe when the original one is not, and more eecient than the original query when this is safe.
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ژورنال
عنوان ژورنال: Algorithmica
سال: 2016
ISSN: 0178-4617,1432-0541
DOI: 10.1007/s00453-016-0162-7