title: PostgreSQL: See query results as scan progresses, rather than wait till end and show all
body: <p>For a simple select query like <code>select column_name from table_name</code> on a very large table, is it possible to have the output being provided as the scan of the table progresses? </p>
  
  <p>If I abort the command after sometime, I expect to get output from the select at least thus far.</p>
  
  <p>Think <code>cat</code>, which I believe won't wait till it completes the full read of the file.</p>
  
  <p>Does MySQL or other RDBMS systems support this?</p>