Could you run this version of your script and report back the output?

# use DBI oracle
my $dbh = DBI->connect(
    "dbi:Oracle:host=server.domain.com; sid=sid; port=1521", "username
+", "password"
) or die "Can't connect to database $DBI::errstr\n";

# The SELECT query
# This query return ~945,000,000,000 records
$sql_chr = qq{
    select column_a, g.column_b, column_c, column_d, column_e 
    from table_f f, table_g g 
    where  f.column_a = g.column_b 
    and column_c != '-/-' 
    and column_d = 'STR' 
    and column_e = 'STR1' 
    and column_a = 9
};

print time;
my $sth_chr = $dbh->prepare( $sql_chr );

print time;

if($sth_chr->execute) {

my $now = time;
print $now;

my $stop = $now + 60;

    my $s=1;
    while( my ( @dat ) = $sth_chr->fetchrow ) {
        $s++;
        last if time() > $stop;
    }
    print $s;
    
}
print time;
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