If let’s say Mysql is slow at performing a task you can check what is the bottleneck using strace to attach to the process.
<span style="color: #00ff00;">$ ps -ef|grep -i mysql</span>
Identify the process id then
<span style="color: #00ff00;">$ strace -cp <pid></span>
Leave it 10 seconds or a minute then
^C. That will tell you where the process is spending its time, e.g. it could just be waiting for the disk if you seen