An example of optimizing a XXX real estate network

This is an SQL statement they developed

 
 

  
  
Select id, title, createdate from table name order by createdate asc limit 334570,10;
 
 

The person who asked this question meant reading the oldest news title and reading 10 records from 334570 rows of data.

The index information is as follows:

650) this. width = 650; "border =" 0 "src =" http://www.bkjia.com/uploads/allimg/131229/1S3524241-0.jpg "alt =" "/>

The optimizer executes the following:

650) this. width = 650; "border =" 0 "src =" http://www.bkjia.com/uploads/allimg/131229/1S3523517-1.jpg "alt =" "/>

This reminds me of an optimization case of the second High-Performance edition.

Let's take a look at the SQL Execution:

650) this. width = 650; "border =" 0 "src =" http://www.bkjia.com/uploads/allimg/131229/1S3522151-2.jpg "alt =" "/>

This is after optimization:

650) this. width = 650; "border =" 0 "src =" http://www.bkjia.com/uploads/allimg/131229/1S352F64-3.jpg "alt =" "/>

The specific reason is that I will not make a shift here. Please read the high-performance MySQL 2nd version. below is the description in the book:

650) this. width = 650; "border =" 0 "src =" http://www.bkjia.com/uploads/allimg/131229/1S3524255-4.jpg "alt =" "/> 650) this. width = 650; "border =" 0 "src =" http://www.bkjia.com/uploads/allimg/131229/1S35251J-5.jpg "alt =" "/>

 

This article is from the "hechun's technical column" blog, please be sure to keep this source http://hcymysql.blog.51cto.com/5223301/1123388