Parallel partition-wise aggregation
    3.
    发明授权
    Parallel partition-wise aggregation 有权
    并行分区聚合

    公开(公告)号:US07779008B2

    公开(公告)日:2010-08-17

    申请号:US11060260

    申请日:2005-02-16

    IPC分类号: G06F17/30

    CPC分类号: G06F9/4494

    摘要: Techniques are provided for performing a parallel aggregation operation on data that resides in a container, such as a relational table. During generation of the execution plan for the operation, it is determined whether partition-wise aggregation should be performed, based on the grouping keys involved in the aggregation and the partition keys used to partition the container. If partition-wise aggregation is to be performed, then the assignments given to the slave processes that are assigned to scan a container are made on a partition-wise basis. The scan slaves themselves may perform full or partial aggregation (depending on whether they are the only scan slaves assigned to the partition). If the scan slaves perform no aggregation, or only partial aggregation, then the scan slaves redistribute the data items to aggregation slaves that are local to the scan slaves.

    摘要翻译: 提供了用于对驻留在诸如关系表的容器中的数据执行并行聚合操作的技术。 在生成操作的执行计划时,基于聚合中涉及的分组密钥和用于分区容器的分区密钥,确定是否应该执行分区聚合。 如果要执行分区聚合,则分配给分配给扫描容器的从属进程的分配是以分区方式进行的。 扫描从站本身可以执行完全或部分聚合(取决于它们是否是分配给分区的唯一扫描从站)。 如果扫描从站不执行聚合或仅执行部分聚合,则扫描从站将数据项重新分配到扫描从站本地的聚合从站。

    Method and mechanism for database partitioning
    6.
    发明申请
    Method and mechanism for database partitioning 有权
    数据库分区的方法和机制

    公开(公告)号:US20050038784A1

    公开(公告)日:2005-02-17

    申请号:US10952390

    申请日:2004-09-27

    IPC分类号: G06F7/00 G06F17/30

    摘要: The present invention is directed to a method and mechanism for partitioning using information not directly located in the object being partitioned. According to an embodiment of the invention, foreign key-primary key relationships are utilized to create join conditions between multiple database tables to implement partitioning of a database object. Also, disclosed are methods and mechanisms to perform partition pruning.

    摘要翻译: 本发明涉及一种使用不直接位于被划分的对象中的信息进行分区的方法和机制。 根据本发明的实施例,利用外键 - 主键关系来创建多个数据库表之间的连接条件以实现数据库对象的分区。 此外,公开了执行分割修剪的方法和机制。

    SQL Execution Plan Verification
    8.
    发明申请
    SQL Execution Plan Verification 有权
    SQL执行计划验证

    公开(公告)号:US20090106219A1

    公开(公告)日:2009-04-23

    申请号:US12188683

    申请日:2008-08-08

    IPC分类号: G06F17/30

    CPC分类号: G06F17/30469 G06F17/30463

    摘要: Approaches, techniques, and mechanisms are disclosed for ensuring that a database command is executed according to a query plan that has been verified to be actually optimal. Except in rare circumstances, a database server does not execute a query plan unless it is first verified by the database server. The database server receives a request to execute a database command. The database server determines an unverified plan is the best plan for satisfying the request. Rather than risk the unknown behavior of an unverified plan, the database server instead satisfies the request according to a verified plan. Subsequently—for example as part of a scheduled job—the database server executes the unverified plan to determine performance statistics. Based at least on the performance statistics, the database server determines whether or not to verify the unverified plan. Techniques for concurrent and optimistic verifications are also disclosed.

    摘要翻译: 公开了方法,技术和机制,以确保根据已被验证为实际最佳的查询计划来执行数据库命令。 除非在极少数情况下,数据库服务器不执行查询计划,除非数据库服务器首先进行了验证。 数据库服务器接收执行数据库命令的请求。 数据库服务器确定未验证的计划是满足请求的最佳方案。 而不是冒险未验证的计划的未知行为,数据库服务器而是根据验证的计划满足请求。 随后 - 例如作为计划作业的一部分 - 数据库服务器执行未验证的计划以确定性能统计信息。 至少基于性能统计,数据库服务器确定是否验证未验证的计划。 还公开了并发和乐观验证的技术。

    Approximating a database statistic
    9.
    发明申请
    Approximating a database statistic 有权
    近似数据库统计

    公开(公告)号:US20080120274A1

    公开(公告)日:2008-05-22

    申请号:US11796102

    申请日:2007-04-25

    IPC分类号: G06F7/00

    摘要: A method and apparatus for approximating a database statistic, such as the number of distinct values (NDV) is provided. To approximate the NDV for a portion of a table, a synopsis of distinct values is constructed. Each value in the portion is mapped to a domain of values. The mapping function is implemented with a uniform hash function, in one embodiment. If the resultant domain value does not exist in the synopsis, the domain value is added to the synopsis. If the synopsis reaches its capacity, a portion of the domain values are discarded from the synopsis. The statistic is approximated based on the number (N) of domain values in the synopsis and the portion of the domain that is represented in the synopsis relative to the size of the domain.

    摘要翻译: 提供了用于近似数据库统计量的方法和装置,例如不同值(NDV)的数量。 为了近似表的一部分的NDV,构建了不同值的概要。 该部分中的每个值都映射到值的域。 在一个实施例中,映射功能是用均匀散列函数实现的。 如果在概要中不存在结果域值,则将域值添加到概要中。 如果概要达到其容量,则域值的一部分将从摘要中被丢弃。 统计量基于概要中的域值的数量(N)和在概要中相对于域的大小表示的域的部分近似。

    Parallel partition-wise aggregation
    10.
    发明申请
    Parallel partition-wise aggregation 有权
    并行分区聚合

    公开(公告)号:US20060182046A1

    公开(公告)日:2006-08-17

    申请号:US11060260

    申请日:2005-02-16

    IPC分类号: H04L12/16 H04Q11/00

    CPC分类号: G06F9/4494

    摘要: Techniques are provided for performing a parallel aggregation operation on data that resides in a container, such as a relational table. During generation of the execution plan for the operation, it is determined whether partition-wise aggregation should be performed, based on the grouping keys involved in the aggregation and the partition keys used to partition the container. If partition-wise aggregation is to be performed, then the assignments given to the slave processes that are assigned to scan a container are made on a partition-wise basis. The scan slaves themselves may perform full or partial aggregation (depending on whether they are the only scan slaves assigned to the partition). If the scan slaves perform no aggregation, or only partial aggregation, then the scan slaves redistribute the data items to aggregation slaves that are local to the scan slaves.

    摘要翻译: 提供了用于对驻留在诸如关系表的容器中的数据执行并行聚合操作的技术。 在生成操作的执行计划时,基于聚合中涉及的分组密钥和用于分区容器的分区密钥,确定是否应该执行分区聚合。 如果要执行分区聚合,则分配给分配给扫描容器的从属进程的分配是以分区方式进行的。 扫描从站本身可以执行完全或部分聚合(取决于它们是否是分配给分区的唯一扫描从站)。 如果扫描从站不执行聚合或仅执行部分聚合,则扫描从站将数据项重新分配到扫描从站本地的聚合从站。