Dynamic Query Re-Optimization
نویسندگان
چکیده
Very long-running queries in database systems are not uncommon in non-traditional application domains such as image processing or data warehousing analysis. Query optimization, therefore, is important. However, estimates of the query characteristics before query execution are usually inaccurate. Further, system conngu-ration and resource availability may change during long evaluation period. As a result, queries are often evaluated with sub-optimal plan conngurations. To remedy this situation, we have designed a novel approach to re-optimize suboptimal query plan conngurations on-they with Conquest | an extensible and distributed query processing system. A dynamic optimizer considers reconnguration cost as well as execution cost in determining the best query plan connguration. Experimental results are presented.
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