single
   <code class="structname">pg_stat_statements</code> entry whenever they have identical query
   structures according to an internal hash calculation.  Typically, two
   queries will be considered the same for this purpose if they are
   semantically equivalent except for the values of literal constants
   appearing in the query.
  </p><div class="note"><h3 class="title">Note</h3><p>
    The following details about constant replacement and
    <code class="structfield">queryid</code> only apply when