sub metasearch {
  my $self = shift;
  # Note: could make dbs return array in array context
  # with 'wantarray'
  my @dbs = @{$self->dbs};

  my @db_socks;
  foreach my $db (@dbs) {
    my $sock = $db->connect;
    send_nonblocking_query($sock);
    push @db_socks, $sock;
  }
  my $timeout_at = time() + $timeout_secs;
  while (@db_socks && time() < $timeout_at) {
    ..select on @db_socks, timing out at timeout_at
    ..handle a wakeup on a socket by reading the response
  }

  # error handling of remaining @db_socks
}