my $failed;
eval {
    local $SIG{ALRM} = sub { die "TIMEOUT\n" }; # N.B. \n required
    eval {
	alarm($seconds);
	... code to execute with timeout here (which may die) ...
	    1;
    } or $failed = 1;
    # outer eval catches alarm that might fire JUST before this alarm(0)
    alarm(0);  # cancel alarm (if code ran fast)
    die "$@" if $failed;
    1;
} or $failed = 1;
if ( $failed ) {
    if ( defined $@ and $@ eq "TIMEOUT\n" ) { ... }
    else { ... } # some other error
}

##</code><code>##

my $failed;
my $seconds = 12;
eval{
    Config::Simple->import_from("".$path."", \%config)
	or die Config::Simple->error();

    my $dbh = DBI->connect("dbi:mysql::".$config{'MySQL.host'}.":".$config{'MySQL.port'}."", 
			   "".$config{'MySQL.user'}."",
			   "".$config{'MySQL.pass'}."",
			   { 'PrintError' => 1, 'RaiseError' => 1 , 'AutoInactiveDestroy' => 1 } 
	) or die "Could not connect to ". $config{'MySQL.host'} .": ". $DBI::errstr ."\n";

    local $SIG{ALRM} = sub { die "db_timeout" };
    eval {
	alarm($seconds);
	$dbh->do("USE Thanos1983");
	    # or die "Error: " .dbh->errstr. "\n";
	1;
    } or $failed = 1;
    # outer eval catches alarm that might fire JUST before this alarm(0)
    alarm(0);  # cancel alarm (if code ran fast)
    die "$@" if $failed;
    1;
} or $failed = 1;

if ( $failed ) {
    if ( defined $@ and $@ eq "TIMEOUT\n" ) { ... }
    else { print "Error\n" } # some other error
}

__END__

$ perl test.pl 
DBD::mysql::db do failed: Unknown database 'Thanos1983' at test.pl line 30.
Error

##</code><code>##

my $sth = $dbh->prepare("SELECT `ID`, `Y-Values` FROM `".$config{'MySQL.table'}."` WHERE 1");

if (!$sth->execute()) {
    die "Error: ". $sth->errstr ."\n";
}