ll return nulls).  This
      feature is intended to support external tools that might wish to avoid
      the overhead of repeatedly retrieving query texts of indeterminate
      length.  Such tools can instead cache the first query text observed
      for each entry themselves, since that is
      all <code class="filename">pg_stat_statements</code> itself does, and then retrieve
      query texts only as needed.  Since the server stores query texts in a
      file, this approach may reduce physical I/O f