title: Is there a good tool for MySQL that will help me optimise my queries and index settings?
body: <p>I use MySQL in a fairly complex web site (PHP driven).</p>
  
  <p>Ideally, there would be a tool I could use that would help me test the SQL queries I am using and suggest better table indexes that will improve performance and avoid table scans.</p>
  
  <p>Failing that, something that will tell me exactly what each query is up to, so I can perform the optimisation myself.</p>
  
  <p>Edit: a simple guide to understanding the output from EXPLAIN ... would also be useful.</p>
  
  <p>Thank you.</p>