How to enable slow query log in mysql command line

Mysql command line method to enable slow query log: Execute the [set global slow_query_log='ON';] statement to enable it. You can check whether the slow query log is enabled by executing the [show variables like "%slow%";] statement.

Specific method:

(Recommended tutorial: mysql tutorial)

Check the default slow speed The query time is 10 seconds

mysql> show variables like "%long%";         
+-----------------+-----------+
| Variable_name   | Value     |
+-----------------+-----------+
| long_query_time | 10.000000 |
+-----------------+-----------+
1 row in set (0.00 sec)

Set to 3 seconds, add global, exit and re-enter to take effect

mysql> set global long_query_time=3;         
Query OK, 0 rows affected (0.00 sec)

Check whether slow query has been enabled

mysql> show variables like "%slow%";         
+---------------------+---------------------------------+
| Variable_name       | Value                           |
+---------------------+---------------------------------+
| log_slow_queries    | OFF                             |
| slow_launch_time    | 2                               |
| slow_query_log      | OFF                             |
| slow_query_log_file | /usr/local/mysql/mysql-slow.log |
+---------------------+---------------------------------+
4 rows in set (0.00 sec)

Enable slow query

mysql> set global slow_query_log='ON';          
Query OK, 0 rows affected (0.28 sec)

Check whether it has been enabled

mysql> show variables like "%slow%";             
+---------------------+---------------------------------+
| Variable_name       | Value                           |
+---------------------+---------------------------------+
| log_slow_queries    | ON                              |
| slow_launch_time    | 2                               |
| slow_query_log      | ON                              |
| slow_query_log_file | /usr/local/mysql/mysql-slow.log |
+---------------------+---------------------------------+
4 rows in set (0.00 sec)

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