code: func (s *Session) SetPoolLimit(limit int) {
  	s.m.Lock()
  	s.poolLimit = limit
  	s.m.Unlock()
  }
docs: // SetPoolLimit sets the maximum number of sockets in use in a single server
  // before this session will block waiting for a socket to be available.
  // The default limit is 4096.
  //
  // This limit must be set to cover more than any expected workload of the
  // application. It is a bad practice and an unsupported use case to use the
  // database driver to define the concurrency limit of an application. Prevent
  // such concurrency "at the door" instead, by properly restricting the amount
  // of used resources and number of goroutines before they are created.