title: SQL Server 2005: disk space taken by dropped columns
body: <p>I have a big table in SQL Server 2005 that's taking about 3.5 GB of space (according to sp_spaceused). It has 10 million records, and several indexes.</p>
  
  <p>I just dropped a bunch of columns from it, such that the record length got reduced to a half, and to my surprise it took zero time to do that. Obviously, sp_spaceused was still reporting the same taken space, SQL server hadn't really done anything when dropping the columns, other than marking them as "dropped".</p>
  
  <p>So I moved all the data from this table into another new table, truncated it, and moved all the data back, so that it'd get all reconstructed.</p>
  
  <p>Now, after that, data is taking 2.8 GB, which IS less than before, but I expected a bigger drop.</p>
  
  <p>Is it possible that the fact that this table originally had these columns is still leaving something there?  </p>
  
  <p>Was truncating it not enough? Should I drop it and create it again with the smaller column set?  </p>
  
  <p>Or is the data really taking 2.8 GB?</p>
  
  <p>Thanks!</p>