Executing CASE expressions containing subqueries
    1.
    发明授权
    Executing CASE expressions containing subqueries 有权
    执行包含子查询的CASE表达式

    公开(公告)号:US08626744B2

    公开(公告)日:2014-01-07

    申请号:US13358779

    申请日:2012-01-26

    IPC分类号: G06F7/00 G06F17/30

    CPC分类号: G06F17/30483

    摘要: Methods and apparatus, including computer program products, implementing and using techniques for executing a query in a computer to retrieve data from a relational database stored on a data storage device. A query is received that contains a CASE expression having one or more subqueries. A query execution plan is generated. The query execution plan uses a parameterized union all operator to keep the semantics of the CASE expression, and a nested loop join operator to drive data across the section of the query execution plan that executes the CASE expression without performing any join operations. The generated query execution plan is executed in the computer to retrieve data from the relational database.

    摘要翻译: 方法和装置,包括计算机程序产品,用于在计算机中执行查询以从存储在数据存储设备上的关系数据库中检索数据的实现和使用技术。 接收到包含具有一个或多个子查询的CASE表达式的查询。 生成查询执行计划。 查询执行计划使用参数化的联合所有运算符来保留CASE表达式的语义,以及嵌套循环连接运算符来驱动执行CASE表达式的查询执行计划部分中的数据,而不执行任何连接操作。 生成的查询执行计划在计算机中执行以从关系数据库检索数据。

    Executing CASE Expressions Containing Subqueries
    2.
    发明申请
    Executing CASE Expressions Containing Subqueries 有权
    执行包含子查询的CASE表达式

    公开(公告)号:US20130198164A1

    公开(公告)日:2013-08-01

    申请号:US13358779

    申请日:2012-01-26

    IPC分类号: G06F17/30

    CPC分类号: G06F17/30483

    摘要: Methods and apparatus, including computer program products, implementing and using techniques for executing a query in a computer to retrieve data from a relational database stored on a data storage device. A query is received that contains a CASE expression having one or more subqueries. A query execution plan is generated. The query execution plan uses a parameterized union all operator to keep the semantics of the CASE expression, and a nested loop join operator to drive data across the section of the query execution plan that executes the CASE expression without performing any join operations. The generated query execution plan is executed in the computer to retrieve data from the relational database.

    摘要翻译: 方法和装置,包括计算机程序产品,用于在计算机中执行查询以从存储在数据存储设备上的关系数据库中检索数据的实现和使用技术。 接收到包含具有一个或多个子查询的CASE表达式的查询。 生成查询执行计划。 查询执行计划使用参数化的联合所有运算符来保留CASE表达式的语义,以及嵌套循环连接运算符来驱动执行CASE表达式的查询执行计划部分中的数据,而不执行任何连接操作。 生成的查询执行计划在计算机中执行以从关系数据库检索数据。

    GENERATING STATISTICAL VIEWS IN A DATABASE SYSTEM
    4.
    发明申请
    GENERATING STATISTICAL VIEWS IN A DATABASE SYSTEM 有权
    在数据库系统中生成统计视图

    公开(公告)号:US20130198165A1

    公开(公告)日:2013-08-01

    申请号:US13361800

    申请日:2012-01-30

    IPC分类号: G06F17/30 G06F7/00

    CPC分类号: G06F17/30463 G06F17/30289

    摘要: Techniques are disclosed for generating statistical views in a database system. In one embodiment, a request is received to execute a database workload. One or more constraints pertaining to executing the database workload is retrieved. The database workload is evaluated to generate multiple statistical view candidates. The statistical view candidates are refined based on the one or more constraints. One or more statistical views are then generated based on the refined statistical view candidates.

    摘要翻译: 公开了用于在数据库系统中生成统计视图的技术。 在一个实施例中,接收到执行数据库工作负载的请求。 检索与执行数据库工作负载有关的一个或多个约束。 评估数据库工作负载以生成多个统计视图候选。 基于一个或多个约束来改进统计视图候选。 然后,基于精细的统计视图候选来生成一个或多个统计视图。

    System and process for evaluating the performance of a database system
    6.
    发明授权
    System and process for evaluating the performance of a database system 有权
    用于评估数据库系统性能的系统和过程

    公开(公告)号:US06615222B2

    公开(公告)日:2003-09-02

    申请号:US09404440

    申请日:1999-09-22

    IPC分类号: G06F1700

    摘要: A system and process for evaluating the performance of an operational database system without interfering with the normal operation of the operational database system is described. The process involves the creation of a test database which contains the system catalogs of the operational database system as user tables. The test database is used to compile queries using these simulated system catalogs. The access plan generated by the compilation in the test database can then be used to evaluate the performance of the queries.

    摘要翻译: 描述了用于在不干扰操作数据库系统的正常操作的情况下评估操作数据库系统的性能的系统和过程。 该过程涉及创建一个测试数据库,其中包含操作数据库系统的系统目录作为用户表。 测试数据库用于使用这些模拟系统目录编译查询。 然后可以使用由测试数据库中的编译生成的访问计划来评估查询的性能。

    AGGREGATE QUERY OPTIMIZATION
    8.
    发明申请
    AGGREGATE QUERY OPTIMIZATION 有权
    综合查询优化

    公开(公告)号:US20090055350A1

    公开(公告)日:2009-02-26

    申请号:US11845031

    申请日:2007-08-24

    IPC分类号: G06F17/30

    CPC分类号: G06F17/30454

    摘要: A method, computer program product, and system for optimizing aggregate queries are provided. The method, computer program product, and system provide for receiving an aggregate query comprising a GROUP BY operation and an aggregate function, creating an access plan for executing the aggregate query, the access plan including a join between an outer relation and an inner relation, and designating the join included in the access plan as an early out join.

    摘要翻译: 提供了一种优化聚合查询的方法,计算机程序产品和系统。 所述方法,计算机程序产品和系统提供用于接收包括GROUP BY操作和聚合函数的聚合查询,创建用于执行所述聚合查询的访问计划,所述访问计划包括外部关系和内部关系之间的连接, 并将访问计划中包含的连接指定为早期连接。