View MySQL Log Files for Troubleshooting

1 year ago
Noah Thompson
2 minutes

To diagnose issues, follow these steps to view the MySQL log files.

  1. Open the MySQL configuration file, which is typically located in either /etc/mysql/my.cnf or /etc/my.cnf. Check which log files and levels are specified in the configuration file.
  2. To log in to the MySQL database, you can use the following command.
mysql -u 用户名 -p
  1. To view the error log file in MySQL, you can use the following command:
SHOW VARIABLES LIKE 'log_error';
  1. To view the MySQL slow query log file, you can use the following command:
SHOW VARIABLES LIKE 'slow_query_log';

If the slow query log is enabled, you can also use the following command to view the path of the slow query log file:

SHOW VARIABLES LIKE 'slow_query_log_file';
  1. To view the general query log file for MySQL, you can use the following command:
SHOW VARIABLES LIKE 'general_log';

If the general query log is enabled, you can also use the following command to view the path of the general query log file:

SHOW VARIABLES LIKE 'general_log_file';
  1. Check the content of the log file using commands like cat, less or tail, for example:
cat /var/log/mysql/error.log

By examining various log files in MySQL, you can identify a range of issues in the database, such as errors, slow queries, and general queries.

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