title: Long-lasting MySQL processes using up to 95% of CPU
body: <p>I'm really new to server-side and I've been administrating a dedicated server for my website.</p>
  
  <p>At peak hours the website is very slow, in order to know why I've been monitoring it using htop.</p>
  
  <p>Some really long-lasting (more than few hours) mysql processes use up to 95% of the CPU !</p>
  
  <p>The thing is I don't know what queries might be the cause of it nor how to monitor it.
  I do have a cron every quarter of hour that sometimes takes a long time to run but the time of the slow down is not always matching cron's.</p>
  
  <p>I've heard of a solution using a cron job killing too long mysql processes but wouldn't it cause discrepancies in the db ?</p>