How to adjust kernel parameters to improve performance with MySQL

MySQL is one of the most popular relational database management systems at present, with excellent stability and performance. However, under high load and large data volumes, MySQL performance may suffer. At this time, the performance of MySQL can be improved by adjusting the kernel parameters. This article will introduce how to adjust kernel parameters through MySQL to improve performance.

1. Understand the kernel parameters of MySQL

The kernel parameters of MySQL refer to a series of parameters that can be adjusted in the database engine. These parameters can affect MySQL performance, such as cache, threads, connections, and storage engines. It is recommended to back up the database before adjusting any kernel parameters to avoid unnecessary losses.

In MySQL, you can view the kernel parameters in the following ways:

1. Use the SHOW VARIABLES command to view all kernel parameters of the current system and their current values;
2. Use SET The command adjusts the performance of MySQL by modifying the values ​​of kernel parameters;
3. Configure the parameters in the my.cnf file.

2. Which kernel parameters need to be adjusted

The kernel parameters of MySQL can usually be divided into the following categories:

1. Memory cache parameters: including cache size, cache Type and cache expiration time, etc. Adjusting these parameters can improve performance by reducing the amount of disk I/O;
2. Connection parameters: Specify the size of the connection pool, and you can optimize performance by adjusting the parameters;
3. Thread parameters: Adjust the number of threads that the server can generate The number of threads allows MySQL to handle more concurrent requests;
4. Storage engine parameters: Adjust the buffer pool size of the storage engine to improve read and write performance;
5. Query cache parameters: After turning on the query cache, The query results will be cached. When there is the same query, it will be obtained directly from the cache without regenerating the results, thereby saving computer resources and improving execution performance.

3. How to adjust MySQL kernel parameters

1. View and modify parameter values

Use the SHOW VARIABLES command to view parameter values, and use the SET command to modify the kernel parameters as needed value. For example:

SHOW VARIABLES LIKE 'connect_timeout';
SET GLOBAL connect_timeout=30;

2. Configure the configuration file

Configure the kernel parameters in the my.cnf file to ensure that the system parameters are still maintained after restarting the MySQL server. For example, if you want to increase the size of the query cache to 128MB, you need to add the following line to the my.cnf file:

query_cache_size = 128M

Here 128M is the size of the cache, which can be modified as needed.

3. Restart MySQL

After modifying the kernel parameters, in order for the parameters to take effect, you need to restart the MySQL server.
Use the following command to restart MySQL:

/etc/init.d/mysql restart

4. Notes

When modifying and adjusting the kernel parameters of MySQL, you should pay attention to the following points:

1. The data must be backed up first;
2. Carefully study the function and impact of each kernel parameter;
3. When modifying the parameter value, you should modify it one by one, and set its value to the optimal value;
4. Suggestions Modify only one or two parameters at a time and observe whether there is a significant change in the system.

5. Summary

MySQL adjusting kernel parameters is an important part of improving database performance. First, understand the different MySQL kernel parameter types and impacts. Next, adjust the pool, memory, cache, connection, storage engine, and query parameters according to the actual situation. Finally, ensure that the modified parameter values ​​are optimal and restart the MySQL server. for the changes to take effect. Through the above steps, the performance and stability of MySQL can be significantly improved.

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