Hamid Pirahesh, Joseph M. Hellerstein, and Waqar Hasan. Extensible/rule based query rewrite optimization in startburst. In Proceedings of the ACM SIGMOD Conference, pages 39--38, 1992.  Home/Search   Document Not in Database   Summary   Related Articles

....possible and in some cases, although possible, may not be efficient. As pointed B (invariant, large) variant, small) invariant, large) A B A C (invariant, large) variant, small) invariant, large) JOIN JOIN JOIN JOIN C (a) Plan 1 (b) Plan 2 Figure 1: Plans for a correlated subquery out in [PHH92] queries that contain non existential or non Boolean factor subqueries, set operators, aggregates, or user defined extension operators (e.g. OUTER JOIN) do not get rewritten. Although it is shown in later work ( SPL96] that some of the queries including aggregates can be decorrelated, there ....

....seen, the rewritten queries usually involve views being shared. Techniques for multiple query optimization on an intra query (as opposed to inter query) basis are desirable to improve the performance of the rewritten queries. Other query rewriting related work has been done in [Kim82, Day87, GW87, PHH92] A comparison of the performance among these techniques can be found in [SPL96] 8 Conclusion In this paper, we first discussed various ways of evaluating a correlated query. We then presented the technique of caching and reusing invariants and showed how to incorporate the invariant feature ....

Hamid Pirahesh, Joseph M. Hellerstein, and Waqar Hasan. Extensible/rule based query rewrite optimization in startburst. In Proceedings of the ACM SIGMOD Conference, pages 39--38, 1992.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC