title: What is the difference between postgresql rebuild index and recreate index, which one is better?
body: <p>I have a table which index size is too big (about 2G). When I restore the database to a VM, the size is only 200M so I need  to rebuild/recreate the index and I will probably do this online.</p>
  
  <p>What is the difference between re-building (reindex) and re-creating the index, and which one is better when I do it online? Particularly, which option allows querying the DB during the operation?</p>