摘要:
A way for progressively refining a query execution plan during query execution in a federated data system is provided. Re-optimization constraints are placed in the query execution plan during query compilation. When a re-optimization constraint is violated during query execution, a model of the query execution plan is refined using a partially executed query to form a new query execution plan. The new query execution plan is compiled. The compiled new query execution plan is executed.
摘要:
Method of cooling an at most partially solidified molten metal during fractional crystallization wherein metal crystals formed have a purer composition than that of the molten metal. Salt in solid form is used to cool the at most partially solidified molten metal.
摘要:
A method and system for automatically and adaptively determining query execution plans for parametric queries. A first classifier trained by an initial set of training points is generated. A query workload and/or database statistics are dynamically updated. A new set of training points is collected off-line. Using the new set of training points, the first classifier is modified into a second classifier. A database query is received at a runtime subsequent to the off-line phase. The query includes predicates having parameter markers bound to actual values. The predicates are associated with selectivities. A mapping of the selectivities into a plan determines the query execution plan. The determined query execution plan is included in an augmented set of training points, where the augmented set includes the initial set and the new set.
摘要:
A method and system for automatically and adaptively determining query execution plans for parametric queries. A first classifier trained by an initial set of training points is generated. A query workload and/or database statistics are dynamically updated. A new set of training points is collected off-line. Using the new set of training points, the first classifier is modified into a second classifier. A database query is received at a runtime subsequent to the off-line phase. The query includes predicates having parameter markers bound to actual values. The predicates are associated with selectivities. A mapping of the selectivities into a plan determines the query execution plan. The determined query execution plan is included in an augmented set of training points, where the augmented set includes the initial set and the new set.
摘要:
A method and system for query problem determination have been disclosed. The method includes receiving a database query; creating a query execution plan for the database query comprising a plurality of query plan operators; and executing the query execution plan, wherein a progress indicator is displayed for each query plan operator. The system includes a query progress monitor, which collects progress information for each query plan operator during the execution of the query execution plan. This progress information is then communicated to a query progress visualizer and a query progress analyzer, which graphically displays the progress information as a progress indicator for each query plan operator and performs debugger type operations, respectively. In this manner, information concerning the progress of the query execution is provided at a query operator level, such that the information may be used to more efficiently debug any problems with the query.
摘要:
A method is disclosed for executing a predetermined query plan, the method comprising: executing a portion of the query plan; providing a reordered query plan; comparing ranking metrics for the query plans; and executing the query plan having the lower ranking metric.
摘要:
There is disclosed a data processing system implemented method, a data processing system, and an article of manufacture for directing a data processing system to maintain a database table associated with an initial maintenance scheduling interval. The data processing system implemented method includes selecting a randomizing factor, and selecting a new maintenance scheduling interval for the database table based on the initial maintenance scheduling interval and the selected randomizing factor.
摘要:
A method for consistent selectivity estimation based on the principle of maximum entropy (ME) is provided. The method efficiently exploits all available information and avoids the bias problem. In the absence of detailed knowledge, the ME approach reduces to standard uniformity and independence assumptions. The disclosed method, based on the principle of ME, is used to improve the optimizer's cardinality estimates by orders of magnitude, resulting in better plan quality and significantly reduced query execution times.
摘要:
A method and system for query problem determination have been disclosed. The method includes receiving a database query; creating a query execution plan for the database query comprising a plurality of query plan operators; and executing the query execution plan, wherein a progress indicator is displayed for each query plan operator. The system includes a query progress monitor, which collects progress information for each query plan operator during the execution of the query execution plan. This progress information is then communicated to a query progress visualizer and a query progress analyzer, which graphically displays the progress information as a progress indicator for each query plan operator and performs debugger type operations, respectively. In this manner, information concerning the progress of the query execution is provided at a query operator level, such that the information may be used to more efficiently debug any problems with the query.
摘要:
A process is disclosed for the production of compounds based on hydrolyzable silanes containing epoxy groups. The process involves adding one of the following substances to a pre-hydrolyzed silicon compound A with at least one hydrolytically non-separable group which includes an epoxy ring in the presence of an alcoholate of zirconium or aluminum: i) a particulate substance B which can be selected from oxides, oxyhydrates, nitrides or carbides of Si, Al and B, and of transition metals, the particle size being 1-100 nm;ii) a surface-active agent, preferably non-ionic;iii) an aromatic polyol with an average molecular weight not exceeding 1000, the resulting compounds being useful to produce coatings and molded bodies with a range of properties, in particular high scratch resistance, lasting hydrophilic characteristics, corrosion resistance, good adhesion and transparency.