title: what does DBCC DBREINDEX('?', ' ', 80) do?
body: <p>What exactly does the following statement do? Does it reindex all tables named '?' with a fill factor of 80% ?</p>
  
  <pre><code>EXEC sp_MSforeachtable @command1="print '?' DBCC DBREINDEX ('?', ' ', 80)"
  </code></pre>
  
  <p>It did improve query time from 23 seconds to almost instantly but I'd like to understand why.</p>