public function minimizarSGMail()
{
    $conn = oci_connect(IC::get('database.username'), IC::get('database.password'), IC::get('database.tns'));
    $linhas = 5;
    $dias = 90;
    $erro = array();

    // Prepara o sql de insert
    $stid = oci_parse($conn, "INSERT INTO TB100442_MAIL_BACKUP (
            SELECT * FROM (
                SELECT * FROM TB100442_MAIL WHERE
                    DATA_INSERCAO <= TO_DATE(SYSDATE-{$dias}) AND
                    ROWNUM <= {$linhas}
                    ORDER BY ID_MAIL DESC
            )
        )"
    );

    $r = oci_execute($stid, OCI_NO_AUTO_COMMIT);
    if (!$r) {
        $e = oci_error($stid);
        array_push($erro, htmlentities($e['message'] . '. Linha: ' . __LINE__));
    }

    // Prepara o sql de exclusao
    $stid = oci_parse($conn, "DELETE FROM TB100442_MAIL WHERE ID_MAIL IN (
            SELECT ID_MAIL FROM (
                SELECT ID_MAIL FROM TB100442_MAIL WHERE
                    DATA_INSERCAO <= TO_DATE(SYSDATE-{$dias})
                    AND ROWNUM <= {$linhas}
                    ORDER BY ID_MAIL DESC
            )
        )"
    );

    $r = oci_execute($stid, OCI_NO_AUTO_COMMIT);
    if (!$r) {
        $e = oci_error($stid);
        array_push($erro, htmlentities($e['message'] . '. Linha: ' . __LINE__));

        // Rollback das mudancas em ambas as tabelas
        oci_rollback($conn);
    }

    // Commita as mudancas em ambas as tabelas
    $r = oci_commit($conn);
    if (!r) {
        $e = oci_error($conn);
        array_push($erro, htmlentities($e['message'] . '. Linha: ' . __LINE__));
    }

    echo '<pre>';
    print_r($erro);
    die;
}