Install MySQL in docker and modify my CNF profile

Preface

Previous experience MySQL After master-slave replication , Find out database Is very slow to read and write , And it happens all the time MySQL Too few connections , A situation that causes the entire database to crash . By modifying the MySQL Medium my.cnf Profile parameters , In order to achieve MySQL Rational use of the maximum performance of relational database .

This article is divided into three aspects to tell ：

One 、Docker install MySQL

 see mysql Mirror image  	
    sudo docker search mysql
 Pull mysql 	
    sudo docker pull mysql  
 # Default to the latest version ( Customizable 5.7)  
 Create a container , And test the , Reference link 
  	sudo docker run --name mysql -e MYSQL\_ROOT\_PASSWORD=123456 -p 3306:3306 -d mysql

Two 、 Connect MySQL

docker Into mysql Container method  	
    1）sudo docker exec -it  Container name  bash
    2）mysql -uroot -p
    3）use mysql
    4）select host, user from user; see root user 
     Judge root Is there a , If there are two, delete them first delete from user where host="%" and user="root";        
     Revise  update user set host = '%' where user = 'root';
     Refresh the permissions  FLUSH PRIVILEGES;    
     Grant remote access  alter user 'root'@'%' identified with mysql\_native\_password by '123456';

3、 ... and 、 Modify configuration file parameters

1. Once the download is complete , Input docker ps Look at the mirror image

2. Start the container ：docker run -p 3307:3306 --name mysql -e MYSQL\_ROOT\_PASSWORD=root -d mysql,docker ps You can view the status

3. Get into MySQL In container ：docker exec -it Container name /bin/bash（PS： In fact, this one follows Linux It's the same as modifying a file , There are many ways , I use the most stupid one .） Replace local file with container file

4. What I want to change here is MySQL Inside my.cnf file . You can use it first ls Look at the catalog file （PS： ls Command to display the contents of the current directory ）

5.tail my.cnfPS：tail The command can be used to view the contents of a file ）

6. function vim Code

    vim /etc/mysql/my.cnf

7. Run the above vim After the code, you may find that it did not execute successfully , because docker There is no... In the container vim Editor , So you have to install it yourself vim Editor （vim Details of installation methods can be found at the end of the article appendix ）

8. Get into my.cnf file

9. Add or modify the configuration according to your own needs , My modified configuration is as follows （ For reference ）

10. Enclosed MySQL Some key parameters of database performance optimization

Key parameter one ：back\_log

requirement MySQL The number of connections you can have . Be the main MySQL Threads get a lot of connection requests in a short time , It works , Then the main thread takes some time ( Short as it is ) Check the connection and start a new thread .

back_log The value is in MySQL How many requests can be stored in the stack in a short period of time before you temporarily stop answering new requests . Only if you expect a lot of connections in a short time , You need to add it , let me put it another way , It's worth the coming TCP/IP The size of the listening queue for the connection . Your operating system has its own limit on the size of this queue . Try to set back_log Higher than the limit of your operating system will be invalid .

When you look at your host process list , Find a lot 264084 | unauthenticated user | xxx.xxx.xxx.xxx | NULL | Connect | NULL | login | NULL To connect to the process , It's going to increase back_log The value of the . The default value is 50, I changed it to 500.

Key parameter 2 ：interactive\_timeout

The number of seconds the server waits for action on an interactive connection before shutting it down . An interactive client is defined as being right mysql_real_connect() Use CLIENT_INTERACTIVE Option customers . The default value is 28800, I changed it to 7200.

Key parameter three ：key\_buffer\_size

The index block is buffered and shared by all threads .key_buffer_size Is the buffer size for the index block , Add it to get better indexes ( For all read and multiply Write ), To you Can afford that much . If you make it too big , The system will start to change pages and really slow down . The default value is 8388600(8M), my MySQL The main engine has 2GB Memory , So I changed it to 402649088(400MB).

Key parameter four ：max\_connections

The number of customers allowed at the same time . Increase this value by mysqld Number of file descriptors required . This number should be increased , otherwise , You will often see Too many connections error . The default value is 100, I changed it to 1024 .

Key parameter five ：record\_buffer

Each thread that performs a sequential scan allocates a buffer of this size for each table it scans . If you do a lot of sequential scanning , You may want to increase the value . The default value is 131072(128K), I changed it to 16773120 (16M)

Key parameter six ：sort\_buffer

Each thread that needs to be sorted allocates a buffer of that size . Increase this value to accelerate ORDER BY or GROUP BY operation . The default value is 2097144(2M), I changed it to 16777208 (16M).

Key parameter 7 ：table\_cache

Number of open tables for all threads . Increasing this value increases mysqld Number of file descriptors required .MySQL For each uniquely open table, you need 2 File descriptors . The default value is 64, I changed it to 512.

Key parameter eight ：thread\_cache\_size

The number of threads that can be reused in . If there is , The new thread gets... From the cache , When disconnected, if there is space , The customer's line is in the cache . If there are many new threads , In order to improve the Performance is acceptable With this variable value . By comparison Connections and Threads_created Variables of state , You can see the effect of this variable . I set it to 80.

Key parameter 9 ：wait\_timeout

The number of seconds the server waits for action on a connection before shutting it down . The default value is 28800, I changed it to 7200.

notes ： Parameters can be adjusted by modifying /etc/my.cnf File and restart MySQL Realization . This is a more cautious job , The above results are just my opinions , According to the hardware of your own host ( Especially the memory size ) Further modification .

11. Use after modification :wq Preservation

12. Reuse tail Check whether the file is modified correctly

tail /etc/mysql/my.cnf 

13. After the configuration file is modified successfully , You can use it to your heart's content MySQL La ！（PS： Because of the limitation of the original design intention of the relational database , In massive data processing and multi table function query, we will encounter I/O Performance bottleneck . So it has distributed 、 High performance 、 High reliability and other characteristics of non relational database （NoSQL） Gradually understood and used by people , It makes up for the congenital deficiency of relational database performance , There's a huge advantage in storing unstructured data . Main stream NoSQL The database has ：Redis、MongoDB and HBase etc. ）

appendix

vim Download and install the editor

In the use of docker When the container , Sometimes it's not installed inside vim, function vim The prompt says ：vim: command not found, This is the time to install vim, When you run the following installation command ：

apt-get install vim 

Error Wrong presentation ：

Reading package lists… Done 
Building dependency tree 
Reading state information… Done
E: Unable to locate package vim 

according to apt Command to download and install software , We need to be right about apt updated ！！！

apt-get update 

The above command is to synchronize  /etc/apt/sources.list and /etc/apt/sources.list.d Index of the source listed in , In this way, we can get the latest software package .

Wait for the update to complete before running the command ：

apt-get install vim 

vim /etc/mysql/mysql.conf.d/mysqld.cnf 

1.apt-get install vim

2.apt-get update

3. complete vim Editor installation