Patent application number | Description | Published |
20080215531 | DETERMINING VALIDITY RANGES OF QUERY PLANS BASED ON SUBOPTIMALITY - A method for approximating a validity range for a domain of cardinalities of input to an optimal query plan is provided. Such a validity range is iteratively approximated using a modified Newton-Raphson method to find roots of cost functions for optimal and alternative query plans, respectively. The Newton-Raphson method is combined with a method of incrementing roots of cost functions, known as input cardinalities, such that discontinuous and non-differentiable points in cost functions are avoided. In this manner, input cardinalities remain within a domain for which a valid range can be specified. Additionally, a robustness measure is determined by a sensitivity analysis performed on an approximated validity range. Using a robustness measure provided by a sensitivity analysis and resultant validity range and, query plan sub-optimality detection is simplified, re-optimization is selectively triggered, and robustness information is provided to a system or user performing corrective actions. | 09-04-2008 |
20090271443 | METHOD FOR DETECTING DATA ATTRIBUTE DEPENDENCIES - A method for detecting data attribute dependencies including obtaining at least one data attribute pair of a dataset to analyze for dependency, obtaining at least one query feedback record related to the data attribute pair, obtaining at least one observation of the data attribute pair from the query feedback record that includes a selectivity and at least one of a first marginal selectivity or a second marginal selectivity, completing the observation, if it does not include the first marginal selectivity and the second marginal selectivity, by estimating the missing marginal selectivity, adjusting the observation if needed to make it logically consistent among a plurality of observations of the data attribute pair, computing a statistic H | 10-29-2009 |
Patent application number | Description | Published |
20080222092 | AUTOMATICALLY DETERMINING OPTIMIZATION FREQUENCIES OF QUERIES WITH PARAMETER MARKERS - A method and system for automatically determining optimization frequencies of queries having one or more parameter markers. Execution plans for a query are generated and each plan is associated with one or more bind value sets. An optimization frequency is selected based on differences between pairs of execution costs where one execution cost of a pair is a cost of executing the query with a bind value set via a first execution plan and the other execution cost of the pair is a cost of optimally executing the query with the bind value set via a second execution plan. The differences are based on maximum selectivity or cardinality distances associated with the bind value sets. If none of the differences exceeds a predefined value, the query is optimized once. If at least one of the differences exceeds the predefined value, the query is reoptimized each time the query is executed. | 09-11-2008 |
20080222093 | AUTOMATICALLY AND ADAPTIVELY DETERMINING EXECUTION PLANS FOR QUERIES WITH PARAMETER MARKERS - A method and system for automatically and adaptively determining query execution plans for parametric queries. A first classifier trained by an initial set of training points is generated. A query workload and/or database statistics are dynamically updated. A new set of training points is collected off-line. Using the new set of training points, the first classifier is modified into a second classifier. A database query is received at a runtime subsequent to the off-line phase. The query includes predicates having parameter markers bound to actual values. The predicates are associated with selectivities. A mapping of the selectivities into a plan determines the query execution plan. The determined query execution plan is included in an augmented set of training points, where the augmented set includes the initial set and the new set. | 09-11-2008 |
20080228831 | METHOD, SYSTEM AND PROGRAM FOR PRIORITIZING MAINTENANCE OF DATABASE TABLES - There is disclosed a data processing system implemented method, a data processing system, and an article of manufacture for directing a data processing system to maintain a database table associated with an initial maintenance scheduling interval. The data processing system implemented method includes selecting a randomizing factor, and selecting a new maintenance scheduling interval for the database table based on the initial maintenance scheduling interval and the selected randomizing factor. | 09-18-2008 |
20090018992 | MANAGEMENT OF INTERESTING DATABASE STATISTICS - A method, system, and computer program product for managing database statistics are provided. The method, system, and computer program product provide for receiving a query for optimizing, collecting statistics specific to the query prior to generating any access plans for executing the query, and generating an access plan for executing the query based on the collected statistics. | 01-15-2009 |
20090070313 | ADAPTIVELY REORDERING JOINS DURING QUERY EXECUTION - A method is disclosed for executing a predetermined query plan, the method comprising: executing a portion of the query plan; providing a reordered query plan; comparing ranking metrics for the query plans; and executing the query plan having the lower ranking metric. | 03-12-2009 |