Home > Database > Mysql Tutorial > body text

SQLServer执行计划成本(续3)

WBOY
Release: 2016-06-07 17:46:55
Original
1279 people have browsed it
循环、哈希与合并连接比较

在分别讨论了循环、哈希与合并连接的执行计划成本规则之后,现在将3个连接类型放到适合各自条件的环境下一起比较。

下面的图2-27显示了循环、哈希与合并连接在1P/2P系统上的启动成本。外部源和内部源启动成本描述了索引搜索的基本成本包括每行成本0.0000011。连接成本也除去第一行,这样似乎仅有个案是少量变化的。4P系统的启动成本仅在索引搜索基本成本(0.003283025)上不同。

2-27.循环、哈希与合并连接在1P/2P系统上索引搜索的启动成本


Related labels:
source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template