our @connection = ($dsn, $user, $passwd, \%options);
our $dbh = DBI->connect_cached( @connection );

sub do_query {
    my = shift;
    $dbh = DBI->connect_cached( @connection );

    ## do query ##
}

##</code><code>##

unless ($dbh->ping) {
    $dbh = DBI->connect(@connection);
}