docs: def _flush(self):
          """
          Deal with pending result-affecting things.
  
          This should always be called before issuing a search.
          """
          remove = self.store.query(_RemoveDocument)
          documentIdentifiers = list(remove.getColumn("documentIdentifier"))
          if VERBOSE:
              log.msg("%s/%d removing %r" % (self.store, self.storeID, documentIdentifiers))
          reader = self.openReadIndex()
          map(reader.remove, documentIdentifiers)
          reader.close()
          remove.deleteFromStore()