Find out slow sql of mysql_MySQL

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Find out slow sql of mysql

 

Recent days, I should do a sql tuning for a mysql database, and I know a bit of mysql db. In order to find the slow sql, i do the slow_query_log on to collect the slow sql.

 

[sql]mysql> show variables like 'slow%';  +---------------------+-------------------------------------------+  | Variable_name       | Value                                     |  +---------------------+-------------------------------------------+  | slow_launch_time    | 2                                         |  | slow_query_log      | ON                                        |  | slow_query_log_file | /opt/mysql_data/mysql/mysql-test-slow.log |  +---------------------+-------------------------------------------+  3 rows in set (0.00 sec)    mysql> set global slow_launch_time=5;  Query OK, 0 rows affected (0.00 sec)    mysql> show variables like 'slow%';  +---------------------+-------------------------------------------+  | Variable_name       | Value                                     |  +---------------------+-------------------------------------------+  | slow_launch_time    | 5                                         |  | slow_query_log      | ON                                        |  | slow_query_log_file | /opt/mysql_data/mysql/mysql-test-slow.log |  +---------------------+-------------------------------------------+  3 rows in set (0.00 sec)  We can read  /opt/mysql_data/mysql/mysql-test-slow.log  to find slow sql.

 

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