docs: function _queryForTargetSessions(url, minDbSeq) {
      var where = { isConnected: true };
      if (minDbSeq) {
        where.connectedAtDbSeq = { gt: minDbSeq };
      }
      return Session.findAll({
          where: where,
          attributes: [
              'sessionId',
              'connectedAtDbSeq',
          ],
          include: [{
              model: Route,
              where: { routeUrl: url, weight: { gt: 0 } },
              attributes: []
          }],
          group: '`Session`.`sessionId`',
      }, { raw: true })
      .then(function(sessions) {
        var sessionIds = [];
        var dbSeq = -1;
        for (var i = 0; i < sessions.length; i++) {
          var session = sessions[i];
          var sessionId = session['sessionId'];
          sessionIds.push(sessionId);
          dbSeq = Math.max(session['connectedAtDbSeq'], dbSeq);
        }
        return { sessionIds: sessionIds, dbSeq: dbSeq };
      })
    }