title: Can achieve save space updating a column with html to null?
body: <p>We have a big table with a column where we save all the html sent by our app. In few months, the table has grown a lot. We have a requirement, the HTML must be saved for two months. We want to delete the HTML after two months, but we don't want to delete the row because the row has information that we need.</p>
  <p>Can we achieve save space in database updating the column to null?
  Do we need to do an AUTOVACUUM if the answers is yes?</p>
  <p>Thanks a lot!</p>