DirectPathReads

Oracle Database SQL Tuning Guide---8 Optimizer Access Paths    

Direct Path Reads
In a direct path read, the database reads buffers from disk directly into the PGA, bypassing the SGA entirely.
The following figure shows the difference between scattered and sequential reads, which store buffers in the SGA, and direct path reads.

Situations in which Oracle Database may perform direct path reads include:

成都创新互联公司长期为近1000家客户提供的网站建设服务,团队从业经验10年,关注不同地域、不同群体,并针对不同对象提供差异化的产品和服务;打造开放共赢平台,与合作伙伴共同营造健康的互联网生态环境。为勐海企业提供专业的做网站、网站建设勐海网站改版等技术服务。拥有十年丰富建站经验和众多成功案例,为您定制开发。

  • Execution of a CREATE TABLE AS SELECT statement

  • Execution of an ALTER REBUILD or ALTER MOVE statement

  • Reads from a temporary tablespace

  • Parallel queries

  • Reads from a LOB segment




 
Direct Path Reads

In a direct path read, the database reads buffers from disk directly into the PGA, bypassing the SGA entirely.

The following figure shows the difference between scattered and sequential reads, which store buffers in the SGA, and direct path reads.

Direct Path Reads

In a direct path read, the database reads buffers from disk directly into the PGA, bypassing the SGA entirely.

The following figure shows the difference between scattered and sequential reads, which store buffers in the SGA, and direct path reads.

Direct Path Reads

In a direct path read, the database reads buffers from disk directly into the PGA, bypassing the SGA entirely.

The following figure shows the difference between scattered and sequential reads, which store buffers in the SGA, and direct path reads.

Direct Path Reads

In a direct path read, the database reads buffers from disk directly into the PGA, bypassing the SGA entirely.

The following figure shows the difference between scattered and sequential reads, which store buffers in the SGA, and direct path reads.

Direct Path Reads
In a direct path read, the database reads buffers from disk directly into the PGA, bypassing the SGA entirely.


The following figure shows the difference between scattered and sequential reads, which store buffers in the SGA, and direct path reads.
Direct Path Reads
In a direct path read, the database reads buffers from disk directly into the PGA, bypassing the SGA entirely.


The following figure shows the difference between scattered and sequential reads, which store buffers in the SGA, and direct path reads.












标题名称:DirectPathReads
文章地址:http://bzwzjz.com/article/poiioc.html

其他资讯

Copyright © 2007-2020 广东宝晨空调科技有限公司 All Rights Reserved 粤ICP备2022107769号
友情链接: 网站设计公司 成都网站制作 成都网站设计 网站制作报价 重庆网站设计 成都网站建设 网站建设方案 重庆网站建设 成都网站制作公司 重庆企业网站建设 成都商城网站建设 成都网站建设公司 成都网站设计 成都网站设计公司 成都网站建设 网站制作公司 成都网站制作 成都网站设计 企业网站设计 成都网站建设流程 成都网站设计 成都网站设计制作公司