Monitor SQL statement execution efficiency according to Mysql slow log _mysql

Monitoring SQL statement execution efficiency based on MySQL slow log

Enable MySQL log-slow-queries (slow query record).

In the Linux environment to find the My.cnf file (generally in/etc/mysql/), and then you may find that the file can not be saved after the modification, because you do not have the appropriate permissions, you can see from the properties of the file owner is root, then the first to open it as root:

sudo nautilus/etc/mysql

Then open the My.cnf file and find the [mysqld] tab and add the following:

log-slow-queries=/path/slow.log– Slow Log save path, the file itself new
long_query_time=2– query for more than 2 seconds
log-queries-not-using-indexes– record queries that do not use indexes

Save, close. Then, if you restart MySQL, you'll get the hint: world-writable config file ' etc my.cnf ' is ignored

Then you need to run this code again:

chmod 644/etc/my.cnf–644 says rw-r–r–

And then restart the service OK.

But note: Log-slow-queries=/path/slow.log for the slow query log storage place, and this directory to have the MySQL running account can write permissions, the directory is generally set to MySQL data storage directory.

I do this: first use the root user into the MySQL data storage directory (typically/var/lib/mysql), create a new Slow.log file (root users can be guaranteed to create new, and then run chmod 644). Then change the owner and the group of the file:

Chown the name of the MySQL running account (you can see the owner and group of other files in the same folder) + decimal + Group name (method with user name)/path/slow.log

Or:

Chown the name of the MySQL run account (you can see the owner and group of other files in the same folder)/path/slow.log

CHGRP group name (method with user name)/path/slow.log

This ensures that MySQL can write logs to Slow.log.