title: SQL Server Indexes - Initial slow performance after creation
body: <p>Using SQL Server 2005. This is something I've noticed while doing some performance analysis.</p>
  
  <p>I have a large table with about 100 million rows. I'm comparing the performance of different indexes on the table, to see what the most optimal is for my test scenario which is doing about 10,000 inserts on that table, among other things on other tables. While my test is running, I'm capturing an SQL Profiler trace which I load in to an SQL table when the test has finished so I can analyse the stats.</p>
  
  <p>The first test run after recreating a different set of indexes on the table is very noticeably slower than subsequent runs - typically about 10-15 times slower for the inserts on this table on the first run after the index creation.</p>
  
  <p>Each time, I clear the data and execution plan cache before the test.</p>
  
  <p>What I want to know, is the reason for this initial poorer performance with a newly created set of indexes?
  Is there a way I can monitor what is happening to cause this for the first run?</p>