摘要:
A method of query pattern matching uses a chain of linked stacks to compactly represent partial results to root-to-leaf query paths, which are then composed to obtain matches for the twig pattern.
摘要:
A method of query pattern matching uses a chain of linked stacks to compactly represent partial results to root-to-leaf query paths, which are then composed to obtain matches for the twig pattern.
摘要:
A method of query pattern matching uses a chain of linked stacks to compactly represent partial results to root-to-leaf query paths, which are then composed to obtain matches for the twig pattern.
摘要:
A method of query pattern matching uses a chain of linked stacks to compactly represent partial results to root-to-leaf query paths, which are then composed to obtain matches for the twig pattern.
摘要:
A method of query pattern matching uses a chain of linked stacks to compactly represent partial results to root-to-leaf query paths, which are then composed to obtain matches for the twig pattern.
摘要:
The use of statistics collected during the parallel distributed execution of the tasks of a job may be used to optimize the performance of the task or similar recurring tasks. An execution plan for a job is initially generated, in which the execution plan includes tasks. Statistics regarding operations performed in the tasks are collected while the tasks are executed via parallel distributed execution. Another execution plan is then generated for another recurring job, in which the additional execution plan has at least one task in common with the execution plan for the job. The additional execution plan is subsequently optimized based at least on the statistics to produce an optimized execution plan.
摘要:
A lightweight physical design alerter can analyze a workload and determine whether a comprehensive tuning session would result in a configuration improvement over the current configuration. The alerter provides a low-overhead procedure that can run during normal operation of a database management system and produce a notification if a current configuration is less than optimal. The alerter can report lower and upper bounds on the improvements that could be obtained if a comprehensive tuning tool is launched. A lower bound can be justified by generating feasible configurations. The disclosed embodiments can be extended to query updates, materialized views, and other physical design features (e.g., partitioning).
摘要:
The min-repro finding technique described herein is designed to ease and speed-up the task of finding a min-repro, a minimum configuration that reproduces a problem in database-related products. Specifically, in one embodiment the technique simplifies transformations in order to find one or more min-repros. One embodiment provides a high-level script language to automate some sub-tasks and to guide the search for a simpler the configuration that reproduces the problem. Yet another embodiment provides record-and-replay functionality, and provides an intuitive representation of results and the search space. These tools can save hours of time for both customers and testers to isolate the problem and can result in faster fixes and large cost savings to organizations.
摘要:
By transforming a query into a product of conditional selectivity expressions, an existing set of statistics on query expressions can be used more effectively to estimate cardinality values. Conditional selectivity values are progressively separated according to rules of conditional probability to yield a set of non-separable decompositions that can be matched with the stored statistics on query expressions. The stored statistics are used to estimate the selectivity of the query and the estimated selectivity can be multiplied by the Cartesian product of referenced tables to yield a cardinality value.
摘要:
Described herein are techniques for Configuration-Parametric Query Optimization (C-PQO) that can improve performance of database tuning tools. When first optimizing a query, a compact representation of the optimization space is generated. The representation can then be used to efficiently produce other execution plans for the query under arbitrary hypothetical configurations.