Abstract: An apparatus, system, and method for determining the maximum supported degree of parallel sort operations in a multi-processor computing environment. An allocation module allocates a minimum number of sort files to a sort operation for each data source that participates in the parallel sort. The allocation module attempts to allocate sort files of one-half the sort operation data source file size, and iteratively reduces the sort file size requests in response to determinations that sort files of the requested size are not available. After allocation, a parallel operation module determines whether there is sufficient virtual storage to execute the sort operations in parallel. If there is not, the parallel operations module collapses the two smallest sort operations, thereby reducing the degree of parallelism by one, and repeats the request. The parallel operation module repeats the process until the sorts are executed or the process fails for lack of virtual storage.

Abstract: An apparatus, system, and method for determining the maximum supported degree of parallel sort operations in a multi-processor computing environment. An allocation module allocates a minimum number of sort files to a sort operation for each data source that participates in the parallel sort. The allocation module attempts to allocate sort files of one-half the sort operation data source file size, and iteratively reduces the sort file size requests in response to determinations that sort files of the requested size are not available. After allocation, a parallel operation module determines whether there is sufficient virtual storage to execute the sort operations in parallel. If there is not, the parallel operations module collapses the two smallest sort operations, thereby reducing the degree of parallelism by one, and repeats the request. The parallel operation module repeats the process until the sorts are executed or the process fails for lack of virtual storage.

Abstract: A method, computer program product, and system for triggering an update of statistics data used by a query optimizer of a relational database management system for determining an optimal execution plan for executing a received query request on a relational database is provided. A system dependent nominal performance value for executing the query request on a database system is determined. Additionally, an average actual performance value is determined by processing the query request. If a comparison between the average actual performance value and the system dependent nominal performance value yields a result which is greater than a first threshold value, an update cost value and a cost saving value are determined. If a comparison between the cost saving value and the update cost value yields a result which is greater than a second threshold value, the statistics data is updated.

Abstract: A system and method for pacing, or controlling, the processing of multiple producers when a consumer requires results from the producers in natural order. This invention regulates the use of system resources between the producers to ensure that the required results are available to the consumer in natural order with minimal waiting and to prevent unneeded advanced processing by the producers. This invention implements a buffer structure such that each producer writes its results to an associated buffer. Each producer compares its buffer's percentage complete against a next and previous producer's buffer. If a producer produces results too rapidly, the producer suspends itself until it is resumed by the consumer or the previous producer. The consumer reads the results from the buffers in producer order.