Mysql Increase Query Speed

In the development of friends especially and MySQL have contact friends will encounter sometimes MySQL query is very slow, of course, I refer to the large amount of data millions level, not dozens of, the following we take a look at the resolution of the query slow way. -Often find developers looking up statements that are not indexed or limit n, which can have a significant impact on the database, such as a large table of tens of millions of records to scan all, or do filesort, and the database and server IO impact. This is the case above the mirrored library. And ...

When it comes to big data, it has to do with Alibaba. The world's leading E-commerce enterprise, the amount of data processed every day is unmatched by any other company, it is also transforming into a real data company--mysql is an important weapon in the transformation of Alibaba. 　　A database architect who interviewed Ali, who believes Ali has the best performance of open source MySQL, beyond any relational database and NoSQL. In the 2009, Oracle acquired the copyright of MySQL by acquiring Sun, and the industry began to question the use of Oracle ...

Intermediary transaction SEO diagnose Taobao guest Cloud host technology Lobby database optimization is a very complex task, because it ultimately requires a good understanding of system optimization. 　　Even though the system or application system does not know much about the optimization effect is good, but if you want to optimize the effect of better, then you need to know more about it. 1, the optimization of the system to run faster the most important factor is the basic design of the database. 　　And you have to be aware of what your system is going to do, and the bottlenecks that exist. The most common system bottlenecks are as follows: ...

First, the importance of the index The index is used to quickly find a column in a particular value of the line. Instead of using an index, MySQL must start with the first record and then read the entire table until it finds the relevant row. The larger the table, the more time it takes. If the table in the query column index, MySQL can quickly reach a location to search the middle of the data file, there is no need to see all the data. Note that if you need to access most of the rows, sequential reads are much faster since we avoid disk searches. If you use Xinhua Dictionary to find "Zhang" the Chinese characters, do not use the directory, then ...

MySQL optimization is very important. The most common and most needed optimization is limit. 　　The limit of MySQL brings great convenience to paging, but when the amount of data is large, the performance of limit is reduced dramatically. The same is 10 data select * FROM Yanxue8_visit limit 10000,10 and select * from Yanxue8_visit limit 0,10 is not a quantitative level ...

1, use the index to traverse the table faster. The index created by default is a non-clustered index, but sometimes it is not optimal. Under non-clustered indexes, the data is physically stored on the data page. Reasonable index design should be based on the analysis and prediction of various inquiries. In general: a. A large number of duplicate values, and often range query (>, <,> =, <=) and order by, group by occurred column, consider the establishment of cluster index; b. Column, ...

1, use the index to traverse the table faster. The index created by default is a non-clustered index, but sometimes it is not optimal. Under non-clustered indexes, the data is physically stored on the data page. Reasonable index design should be based on the analysis and prediction of various inquiries. In general: a. There are a large number of duplicate values, and often range query (>, <,> =, <=) and order by, group by occurred columns, consider the establishment of cluster index; Column, and each column contains duplicate values ​​can be ...

MySQL database sql statement commonly used optimization methods 1. Query optimization, should try to avoid full table scan, should first consider where and order by the columns involved in the establishment of the index. 2. Should be avoided in the where clause on the field null value judgment, otherwise it will cause the engine to abandon the use of indexes and full table scan, such as: select id from t where num is null You can set the default value of num 0, to ensure that Num column table does not null value ...

Intermediary transaction http://www.aliyun.com/zixun/aggregation/6858.html ">seo diagnose Taobao guest cloud host technology Hall of the current web2.0 program, a big bottleneck is the database swallow metric." 　　However, how to determine the bottleneck of the system is a database, because only to determine the database is the bottleneck of the entire system, we have to optimize him, after all, there are so many needs to wait for us to do. 　　How do I determine that a database is a bottleneck? ...

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