公开(公告)号：US09063982B2

公开(公告)日：2015-06-23

申请号：US13748670

申请日：2013-01-24

申请人： International Business Machines Corporation

发明人： Robert Joseph Bestgen ,  Shantan Kethireddy ,  Jeffrey Wayne Tenner

IPC分类号： G06F11/30 ,  G06F17/30

CPC分类号： G06F17/3053 ,  G06F17/30545

摘要： A query facility for database queries dynamically determines whether selective portions of a database table are likely to benefit from separate query execution strategies, and constructs an appropriate separate execution strategies accordingly. Preferably, the database contains at least one relatively large table comprising multiple partitions, each sharing the definitional structure of the table and containing a different respective discrete subset of the table records. The query facility compares metadata for different partitions to determine whether sufficiently large differences exist among the partitions, and in appropriate cases selects one or more partitions for separate execution strategies. Preferably, partitions are ranked for separate evaluation using a weighting formula which takes into account: (a) the number of indexes for the partition, (b) recency of change activity, and (c) the size of the partition.

摘要翻译： 用于数据库查询的查询工具动态地确定数据库表的选择性部分是否可能受益于单独的查询执行策略，并相应地构建适当的单独的执行策略。 优选地，数据库包含至少一个包括多个分区的相对较大的表，每个分区共享表的定义结构，并且包含表记录的不同相应离散子集。 查询设施比较不同分区的元数据，以确定分区之间是否存在足够大的差异，并且在适当的情况下选择一个或多个分区用于单独的执行策略。 优选地，使用考虑到的加权公式对分区进行分级评估：（a）分区的索引的数量，（b）更改活动的新近度，以及（c）分区的大小。

公开(公告)号：US20130132405A1

公开(公告)日：2013-05-23

申请号：US13748670

申请日：2013-01-24

申请人： INTERNATIONAL BUSINESS MACHINES CORPORATION

发明人： Robert Joseph Bestgen ,  Shantan Kethireddy ,  Jeffrey Wayne Tenner

IPC分类号： G06F17/30

CPC分类号： G06F17/3053 ,  G06F17/30545

摘要： A query facility for database queries dynamically determines whether selective portions of a database table are likely to benefit from separate query execution strategies, and constructs an appropriate separate execution strategies accordingly. Preferably, the database contains at least one relatively large table comprising multiple partitions, each sharing the definitional structure of the table and containing a different respective discrete subset of the table records. The query facility compares metadata for different partitions to determine whether sufficiently large differences exist among the partitions, and in appropriate cases selects one or more partitions for separate execution strategies. Preferably, partitions are ranked for separate evaluation using a weighting formula which takes into account: (a) the number of indexes for the partition, (b) recency of change activity, and (c) the size of the partition.

摘要翻译： 用于数据库查询的查询工具动态地确定数据库表的选择性部分是否可能受益于单独的查询执行策略，并相应地构建适当的单独的执行策略。 优选地，数据库包含至少一个包括多个分区的相对较大的表，每个分区共享表的定义结构，并且包含表记录的不同相应离散子集。 查询设施比较不同分区的元数据，以确定分区之间是否存在足够大的差异，并且在适当的情况下选择一个或多个分区用于单独的执行策略。 优选地，使用考虑到的加权公式对分区进行分级评估：（a）分区的索引的数量，（b）更改活动的新近度，以及（c）分区的大小。