title: Mysql performance on 6 million row table
body: <p>One day I suspect I'll have to learn hadoop and transfer all this data to a non-structured database, but I'm surprised to find the performance degrade so significantly in such a short period of time. </p>
  
  <p>I have a mysql table with just under 6 million rows. 
  I am doing a very simple query on this table, and believe I have all the correct indexes in place.</p>
  
  <p>the query is</p>
  
  <pre>
  SELECT date, time FROM events WHERE venid='47975' AND date>='2009-07-11' ORDER BY date
  </pre>
  
  <p>the explain returns</p>
  
  <pre>
  id  select_type     table   type    possible_keys   key     key_len     ref     rows    Extra
  1   SIMPLE  updateshows     range   date_idx    date_idx    7   NULL    648997  Using where
  </pre>
  
  <p>so i am using the correct index as far as I can tell, but this query is taking 11 seconds to run. </p>
  
  <p>The database is MyISAM, and phpMyAdmin says the table is 1.0GiB.</p>
  
  <p>Any ideas here?</p>
  
  <p>Edited: 
  The date_idx is indexes both the date and venid columns. Should those be two seperate indexes?</p>