高性能MySQL笔记-第5章Indexing for High Performance-003索引的作用
2016-04-12 11:14
656 查看
一、
1.
1). Indexes reduce the amount of data the server has to examine.
2). Indexes help the server avoid sorting and temporary tables.
3). Indexes turn random I/O into sequential I/O.
Lahdenmaki and Leach’s book also introduces a three-star system for grading how suitable an index is for a query. The index earns one star if it places relevant rows adjacent to each other, a second star if its rows are sorted in the order the query needs,and a final star if it contains all the columns needed for the query.
1.
1). Indexes reduce the amount of data the server has to examine.
2). Indexes help the server avoid sorting and temporary tables.
3). Indexes turn random I/O into sequential I/O.
Lahdenmaki and Leach’s book also introduces a three-star system for grading how suitable an index is for a query. The index earns one star if it places relevant rows adjacent to each other, a second star if its rows are sorted in the order the query needs,and a final star if it contains all the columns needed for the query.
相关文章推荐
- mysql事务隔离级别
- mysql常用命令集锦
- Keepalived构建双主MySQL
- Mysql初始化root密码和允许远程访问
- DatabaseMetaData 获取mysql表和字段注释
- mysql触发
- Invalid use of group function解决办法
- mysql 优化(有自己的笔记,看法)
- Ubuntu安装mysql的步骤和配置总结
- 高性能MySQL笔记-第5章Indexing for High Performance-002Hash indexes
- MySQL主键学习总结
- mysql知识积累
- Mysql修改数据库名
- MySQL性能优化的21个最佳实践 和 mysql使用索引
- MySQL性能优化的21个最佳实践 和 mysql使用索引
- MySQL性能优化的21个最佳实践 和 mysql使用索引
- Mysql 左连接取出一条数据
- mysql性能优化二
- MySql索引原理及慢查询优化
- 三种在MySQL中修改root密码的方法