title: Is count(*) really expensive?
body: <p>I have a page where I have 4 tabs displaying 4 different reports based off different tables. </p>
  
  <p>I obtain the row count of each table using a <code>select count(*) from &lt;table&gt;</code> query and display number of rows available in each table on the tabs. As a result, each page postback causes 5 <code>count(*)</code> queries to be executed (4 to get counts and 1 for pagination) and 1 query for getting the report content.</p>
  
  <p>Now my question is: are <code>count(*)</code> queries really expensive -- should I keep the row counts (at least those that are displayed on the tab) in the view state of page instead of querying multiple times? </p>
  
  <p>How expensive are COUNT(*) queries ?</p>