MySql's behavior log and slow query: how to quickly locate performance problems

With the rapid development of application systems, how to effectively solve system performance problems has become increasingly important. For applications that use MySql database, behavior logs and slow queries are two important tools for locating performance problems. This article will introduce MySql's behavior logs and slow queries, and discuss how to use these two tools to quickly locate performance problems.

1. MySql Behavior Log

The MySql behavior log is a log that records all operations performed by the database server. By viewing the behavior log, we can understand what operations the database server performed and when these operations were performed. MySql's behavior logs are divided into two types: binary logs and query logs.

1. Binary log

MySql’s binary log is a file-based log that records all update operations to the database. These update operations include insert, update, and delete operations. Binary logs are often used for disaster recovery and data recovery. By analyzing the binary log, we can find out the changes in the database within a certain period of time.

2. Query log

The query log of MySql records all operations requested by the client, including query statements and non-query operations. By looking at the query log, we can learn what operations the client performed at what time. Query logs can help us find and locate slow queries.

2. MySql slow query

The slow query of MySql refers to the query whose execution time exceeds the threshold. The query time threshold can be specified through the configuration file or directly setting the annotation of the query statement. MySql's slow query log records all queries whose execution time exceeds the threshold. By looking at the slow query log, we can determine which query statements take a long time to execute and the reason for the long execution time.

3. How to quickly locate performance problems

Using MySql's behavior logs and slow queries is an important means of locating performance problems. In actual use, we can quickly locate performance problems through the following steps.

1. Turn on the behavior log and slow query log

We can enable and configure the behavior log and slow query log through the MySql configuration file. When turning on behavior logs, we need to determine the log type and the location of the log file. At the same time, we also need to clean the logs regularly to avoid the problem of excessively large log files.

2. View the behavior log

We can understand the operation of the database server by viewing the behavior log. By analyzing the behavior logs, we can determine which operations are performed more frequently, which operations take longer to perform, and the impact of the operations on database performance.

3. View the slow query log

We can find out the queries whose execution time exceeds the threshold by viewing the slow query log. By analyzing query statements and execution plans, we can determine which query statements need to be optimized and the direction of optimization.

4. Optimize query statements

Optimization of query statements is a key step to improve database performance. We can optimize query statements in the following ways:

(1) Use indexes: Indexes are a key factor in improving query speed. We can create appropriate indexes based on query conditions and data distribution.

(2) Avoid full table scan: Full table scan is one of the main causes of query performance bottleneck. We can avoid full table scans by optimizing query conditions.

(3) Reduce connection queries: Connection queries are another cause of query performance bottlenecks. We can reduce the number of connection queries by changing the query conditions or table structure.

Summary

MySql’s behavior log and slow query are important tools for locating performance problems. By enabling and configuring behavior logs and slow query logs, and optimizing query statements based on log information, we can quickly solve database performance problems and improve application response speed and user experience.

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