If you know how to enable slow query in MySQL it’s easy to setup. It can help you analyze the database server response time. you can enable and check a slow query log when you configure with a single command in MySQL.
By default, slow_query_log is off in MySQL 5.5. This helps you to find out which query is taking a long time to execute than the given threshold.
How To Enable Slow Query In MySQL:
We can achieve these either by adding a permanent setting or temporary basis without restart the MySQL service. There are two ways of checking slow_query_log is enabled or not.
Method 1 : show variables like “slow_query_log”;
Method 2 : mysqladmin var |grep log_slow_queries
As you can see slow_query_log is “off“. So let’s enable it by the globally thorough command in MySQL if you want to enable it permanent you will have to put this in my.cnf file.
We can use the below command to Enable on the server for temporary.
SET GLOBAL slow_query_log = 1;
In a similar way, we can use the below command For Disable on the server.
SET GLOBAL slow_query_log = 0;
You need to Set the slow log query file path using the command line for temporary.
SET GLOBAL slow_query_log_file = '/var/log/mariadb/my-slow.log';
Now Check slow query will be “ON“.
show variables like "slow_query_log";
if you need to keep those settings permanent, we have to add those parameters in my.cnf file and restart the MySQL service.
As you can see, By Default, the slow query log file is located at /var/lib/mysql/mysql-slow.log
Now restart the MySQL service to make changes,
You’re done.check slow query log configure slow query log check slow query log enable slow query log