DBD::Sybase rollback()

[Henri Asseily]

Hello,
I have the following code using DBD::Sybase under apache 1.3/mod_perl 
1.xx, where AutoCommit is off:

        $dbh->{RaiseError} = 1;
        eval {
                $sth = $dbh->prepare_cached('exec xx ?');
                $sth->bind_param(1, $a,           { TYPE => SQL_INTEGER 
});
                $sth->execute;
                $sth->finish;

                [ other non-dbi stuff being done here ... ]
                $dbh->commit;
        };
        if ($@) {
                my $prev_error = $@;
                eval { $dbh->rollback };
                $dbh->{RaiseError} = 0;
                return ([ -999, "Got error: $prev_error"]);
        }
        $dbh->{RaiseError} = 0;
I know that the DBI docs say that we technically can simply rollback a 
dbh without worrying about finishing a sth, but is that certainly the 
case for all DBDs? I seem to have a problem where if the statement 
execute fails due to for example a unique index duplicate, the apache 
process hangs with infinite loop AFTER it successfully fully processes 
the request and returns properly. That is very weird to say the least.

Any ideas?
Thanks.