公开(公告)号：US20160378829A1

公开(公告)日：2016-12-29

申请号：US14753179

申请日：2015-06-29

Applicant: Oracle International Corporation

Inventor： David VENGEROV ,  Mohamed ZAIT ,  Sunil P. CHAKKAPPEN ,  Andre MENCK

IPC: G06F17/30

CPC classification number: G06F16/24545

Abstract: A system performs database management. The system receives a request for a query of a plurality of tables under a join condition on an attribute and determines a uniform mapping that maps a domain of the attribute into a set of numbers, where the domain of the attribute includes all attribute values taken by the attribute in the tables. Then, for a row in a table, the system includes the row into a synopsis of the table if the row includes an attribute value that is mapped by the uniform mapping to a number less than an inclusion probability associated with the table. The system obtains a plurality of synopsis for the tables by repeating the including for all rows in the table and for all tables, and determines, based on the plurality of synopsis, an estimate join size of the tables under the join condition.

Abstract translation: 系统执行数据库管理。 系统在属性的接合条件下接收对多个表的查询的请求，并且确定将属性的域映射成一组数字的统一映射，其中属性的域包括由 表中的属性。 然后，对于表中的一行，如果行包含通过统一映射映射到小于与表相关联的包含概率的数字的属性值，则系统将行包含在表的概要中。 系统通过对表中的所有行重复包括表和所有表来获得表的多个概要，并且基于多个概要确定在连接条件下的表的估计连接大小。