Multiple Query Optimization with Depth-First Branch-and-Bound and Dynamic Query Ordering

Dynamic Query Re-Optimization

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...

Dynamic Query Optimization and Query Processing in Multidatabase Systems

Multiple Range Query Optimization

In order to answer efficiently range queries in 2-d R-trees, first we sort queries by means of a space filling curve, then we group them together, and finally pass them for processing. Initially, we consider grouping of pairs of requests only, and give two algorithms with exponential and linear complexity. Then, we generalize the linear method, grouping more than two requests per group. We eval...

Query Optimization for Dynamic Imputation

Missing values are common in data analysis and present a usability challenge. Users are forced to pick between removing tuples withmissing values or creating a cleaned version of their data by applying a relatively expensive imputation strategy. Our system, ImputeDB, incorporates imputation into a costbased query optimizer, performing necessary imputations onthe-fly for eachquery. This allows u...

Query Optimization for Dynamic Graphs

Given a query graph that represents a pattern of interest, the emerging pattern detection problem can be viewed as a continuous query problem on a dynamic graph. We present an incremental algorithm for continuous query processing on dynamic graphs. The algorithm is based on the concept of query decomposition; we decompose a query graph into smaller subgraphs and assemble the result of subquerie...