title: MySQL: Is it faster to use inserts and updates instead of insert on duplicate key update?
body: <p>I have a cron job that updates a large number of rows in a database. Some of the rows are new and therefore inserted and some are updates of existing ones and therefore update.</p>
  
  <p>I use insert on duplicate key update for the whole data and get it done in one call.</p>
  
  <p>But- I actually know which rows are new and which are updated so I can also do inserts and updates seperately.</p>
  
  <p>Will seperating the inserts and updates have advantage in terms of performance? What are the mechanics behind this ?</p>
  
  <p>Thanks!</p>