Patent application number | Description | Published |
20080256024 | Portable and Iterative Re-Usable Suboptimization of Database Queries - A method, apparatus and program product to optimize a database query. A query plan is generated for the database query where the query plan includes first and second subplans. Cached optimization data associated with the first subplan and generated during evaluation of another query plan for a previous query that uses the first subplan is retrieved. The first subplan is evaluated for resource cost using the retrieved optimization data. The second subplan is also evaluated for resource cost. The query plan is then evaluated for resource cost based upon the evaluations of resource cost for the first and second subplans. A query plan is selected based on evaluations of resource cost and the plan is executed to generate a result set. | 10-16-2008 |
20080256025 | Database Query Optimization Utilizing Remote Statistics Collection - A method, apparatus and program product to optimize a database query. In a first system having a first dataspace, a query plan is generated for the database query. Remote statistics collection associated with the database query is initiated on a second system having a second dataspace. The remote statistics collection uses the second dataspace, which includes a current copy of at least a portion of the first dataspace on the first system. Database statistics are collected for the first system by analyzing the second dataspace and then communicating the collected database statistics to the first system for use in optimizing database queries executed by the first system. | 10-16-2008 |
20080301085 | Dynamic Database File Column Statistics for Arbitrary Union Combination - Embodiments of the invention provide techniques for generating database statistics for optimizing union queries. In general, working sets including samples of values in database columns are persistently maintained in a database. To optimize a union query, the working sets describing the columns included in the union query are combined to generate an ad hoc working set. The ad hoc working set is then used to generate a database statistic describing the combined columns. In another embodiment, working sets may also be maintained for generating statistics for optimizing non-union queries, thus enabling statistics to be refreshed more frequently. | 12-04-2008 |
20090248618 | Database Query Processing with Dynamically Activated Buffers - A method, apparatus and program product dynamically activate and/or deactivate buffers during execution of a database query. The dynamic deactivation and activation is based on the monitoring of information associated with the consumption of data by a plurality of threads during execution of an access plan for the database query. By doing so, the selection of a less optimal buffer position during optimization may be replaced with a more optimal buffer position during runtime, often resulting in improved query performance and parallelism. | 10-01-2009 |
20090319474 | Aggregating Database Queries - Embodiments of the invention provide techniques for aggregating database queries for energy efficiency. In one embodiment, queries received by a DBMS are aggregated and staged according to hard-disk drives required for query execution. Each group of queries accessing a given drive may be dispatched for execution together. Further, the queries received by a DBMS may be matched to patterns of previously received queries. The matching patterns may be used to predict other queries which are likely to be received by the DBMS. The received queries may be staged to be dispatched with the predicted queries. By aggregating queries to be executed, access to each hard-disk drive may be optimized, thus reducing the overall energy consumption required for executing the queries. | 12-24-2009 |
20090319475 | Grouping Predicted Database Queries - Embodiments of the invention provide techniques for aggregating database queries for energy efficiency. In one embodiment, queries received by a DBMS are aggregated and staged according to hard-disk drives required for query execution. Each group of queries accessing a given drive may be dispatched for execution together. Further, the queries received by a DBMS may be matched to patterns of previously received queries. The matching patterns may be used to predict other queries which are likely to be received by the DBMS. The received queries may be staged to be dispatched with the predicted queries. By aggregating queries to be executed, access to each hard-disk drive may be optimized, thus reducing the overall energy consumption required for executing the queries. | 12-24-2009 |
20100036804 | Maintained and Reusable I/O Value Caches - Embodiments of the invention provide techniques for maintaining I/O value caches for database queries. Each maintained cache may be configured for use with a particular database query. Each cache may be persistently maintained in a system, meaning the cache is not automatically deleted after some period of time, and may thus be used to process subsequent instances of the same query. By use of the maintained cache, executing subsequent instances of the query may be avoided, thus saving time and system resources. Further, the maintained cache may be adapted to process other queries having similar characteristics to the initial query. The data included in each cache may be refreshed as required by changes to the underlying data. | 02-11-2010 |
20100036805 | System Maintainable and Reusable I/O Value Caches - Embodiments of the invention provide techniques for maintaining I/O value caches for database queries. Each maintained cache may be configured for use with a particular database query. Each cache may be persistently maintained in a system, meaning the cache is not automatically deleted after some period of time, and may thus be used to process subsequent instances of the same query. By use of the maintained cache, executing subsequent instances of the query may be avoided, thus saving time and system resources. Further, the maintained cache may be adapted to process other queries having similar characteristics to the initial query. The data included in each cache may be refreshed as required by changes to the underlying data. | 02-11-2010 |
20100287206 | MAINTAINED SYMBOL TABLE ONLY INDEX - A method, apparatus and program product is provided for optimizing a database query. A query syntax, system generated predicates, and requisite statistics of the database query are analyzed to determine if a predicate structure is a good candidate for a symbol table only data structure. The predicate structure is analyzed to determine if the predicate structure is already encompassed by an encoded vector index. The symbol table only data structure is generated for at least one column in a database table without generating a corresponding vector data structure from an encoded vector index if the predicate structure is a good candidate and not encompassed by an encoded vector index. The symbol table only data structure is maintained by detecting a change in data associated with the symbol table only data structure and updating the symbol table only data structure to reflect the change in the data. | 11-11-2010 |