Join Predicate Pushdown 最早看到这个优化功能,是在Oracle著名的CBQT Paper中,关于这篇文章的解读有很多,笔者也写过一篇《henry liang:Cost-based query transformation in Oracle》。 里面的一个章节介绍了这个优化:Join Predicate PushDown(JPPD),虽然篇幅不多,但还是非常准确的切中了变换的核心: 适用条件 在查询中...
Join Predicate Pushdown 最早看到这个优化功能,是在Oracle著名的CBQT Paper中,关于这篇文章的解读有很多,笔者也写过一篇《henry liang:Cost-based query transformation in Oracle》。(内容详见:https://zhuanlan.zhihu.com/p/372430733) 里面的一个章节介绍了这个优化:Join Predicate PushDown(JPPD),虽然篇幅不多,但...
The decision whether to push down join predicates into a view is determined by evaluating the costs of the outer query with and without the join predicate pushdown transformation under Oracle's cost-based query transformation framework. The join predicate pushdown transformation applies to both non-me...
During optimization, join predicate push down may be used to generate many transformed queries for comparison. The number of query transformations performed for comparison is managed.Ahmed, RafiLee, AllisonDas, DineshR. Ahmed, A. Lee and D. Das. Join Predicate Push-Down Optimizations. US Patent...
Facebook Twitter Google Share on Facebook JPPD (redirected fromJoin Predicate Push-Down) AcronymDefinition JPPDJoin Predicate Push-Down Copyright 1988-2018AcronymFinder.com, All rights reserved. Suggest new definition Want to thank TFD for its existence?Tell a friend about us, add a link to thi...
During Join predicate (join中谓词) 在join中on 语句中的谓词,例如:在 R1 join R2 on R1.x = 5,R1.x = 5 我们称之为 join中谓词 After Join predicate (join后谓词) 在join中,位于where中的谓词 2. join type 根据当前spark版本,我们把join类型分为以下多种类型,也就是我们进行验证的各种join类型 ...
Preserved Row table (留存表) 在join操作中返回所有行的表Null Supplying table (补空表) 在join操作中,对于不匹配的行,补bull的表During Join predicate (join中谓词) 在join中on 语句中的谓词,例如:在 R1 join R2 on R1.x = 5,R1.x = 5 我们称之为 join中谓词After Join predicate (join后谓词)...
1.1 PPD – Predicate Push Down(谓词下推): 谓词下推包含两个内容,第 1 个是检索条件下推,第 2 个是查询字段下推。举例如下: orders: 订单表,每个订单一条记录 lineitem:订单明细表,每个订单中每个物品一条记录,按 orderkey 和 orders 表关联。
During Join predicate (join中谓词) 在join中on 语句中的谓词,例如:在 R1 join R2 on R1.x = 5,R1.x = 5 我们称之为 join中谓词 After Join predicate (join后谓词) 在join中,位于where中的谓词 2. join type 根据当前spark版本,我们把join类型分为以下多种类型,也就是我们进行验证的各种join类型 ...
To get the same result you need push down predicate. It's not so stable yet. 'set enable_optimize_predicate_expression = 1'. When enabled optimizer move WHERE clause from last JOIN to the first ones if possible. So, much less rows would be selected and results would be much better. ...