| 摘要 |
Techniques are provided for improving performance of parallel execution plans that include serial operations. A database server generates a parallel execution plan and includes one or more serial data flow objects in the parallel execution plan, each data flow object including one or more serial row sources. A parallel selector row source is associated with each serial data flow object included in the parallel execution plan. Each parallel selector row source coordinates with a query coordinator process the execution of the associated serial data flow object. In the event that that a plurality of serial data flow objects are included in a parallel execution plan, serial row sources included in the serial data flow objects may be executed concurrently by a separate parallel slave process, instead of sequential execution of each serial row source by the query coordinator process. |
