docs: function (conn, opts) {
              opts = opts || {};
              var s = opts.prepare;
              var logConnectionExecute = comb("__logConnectionExecute");
              if (s) {
                  s = this.literal(s);
                  var self = this;
                  return this.__logConnectionExecute(conn, "XA END " + s)
                      .chain(function () {
                          return self.__logConnectionExecute(conn, "XA PREPARE " + s);
                      })
                      .chain(function () {
                          return self.__logConnectionExecute(conn, "XA ROLLBACK " + s);
                      });
              } else {
                  return this._super(arguments);
              }
          }