摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
This is an example of a new method for optimization of database queries which uses an asynchronous task which keeps the most current status of the database objects by directly interfacing the existing storage management system. This asynchronous task in combination with query plan and cache data is able to aid in detecting and choosing “warm” query costing alternatives. The cold/warm status information of the asynchronous task helps query optimizer to determine: if it is suitable to use “warm” costing for a new query optimization; validate previous decisions to use a “warm”-optimized query plan, when it comes to potentially reuse and run with such a plan again; decide whether it's worthwhile to still cache such a plan in the plan cache.
摘要:
An apparatus, program product and method identify a range of values in a table and advise the generation of a maintained index over the identified range of values. Additionally, a method that determines a range of values and generates a maintained temporary index is also provided. By doing so, the maintained index that was advised may be generated over the range of values in the column and used to access data in the table.
摘要:
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.
摘要:
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.