title: UPDATE or INSERT & DELETE? Which is better for storage / performance with large text columns?
body: <p>I have a Postgres DB as part of an application that
  currently has text fields being populated with about 300K of text.</p>
  <p>There are about 3 columns in the table that can routinely be populated
  with this amount of information. This is causing the tables to be over
  a gig for about 100 rows. I'd like to delete the data from those
  columns without deleting the rest of the information in the row.</p>
  <p>Is <code>UPDATE</code> to set columns to <code>''</code> better than <code>INSERT INTO SELECT</code> where I just pick columns I need and then <code>DELETE</code> the existing row? It's a 3rd party application so rewriting the way that they store the data isn't possible at this point.</p>