Why Is My MySQL Server Using High CPU, and How Can I Fix It?

MySQL High CPU Usage

Background:

A user experiences high CPU usage on their server, particularly by MySQL. Despite optimizing tables and utilizing persistent connections, the issue persists.

Causes and Solutions:

1. Disable Persistent Connections:

Persistent connections can often be detrimental, leading to higher CPU usage. Disable them to resolve this.

2. Check User Permissions:

Ensure that remote connections to MySQL are restricted to authorized users to prevent potential security breaches and excessive CPU consumption.

3. Enable Slow Query Logging:

Activate the MySQL Slow Query Log to identify queries that take an extended time to execute, potentially locking up critical tables.

4. Analyze the Process List:

During high CPU load, run the "SHOW PROCESSLIST" command to view the status of active and pending queries. Examine the query text and duration to pinpoint problematic queries.

5. Optimize Memory Allocations:

Adjust memory settings such as buffer sizes, table cache, query cache, and innodb_buffer_pool_size (for InnoDB tables) to improve query performance and reduce CPU load.

6. Utilize Profiling Tools:

Implement a profiler to analyze the queries executed by your application, identify duplicates, and measure their duration to uncover performance bottlenecks. Consider using PHP Profiler or other available tools.

Additional Resources:

• [How MySQL Uses Memory](https://dev.mysql.com/doc/refman/5.7/en/memory-use.html)
• [MySQL System Variables](https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html)

The above is the detailed content of Why Is My MySQL Server Using High CPU, and How Can I Fix It?. For more information, please follow other related articles on the PHP Chinese website!