php 连接oracle 导出百万级数据

1，我们一般做导出的思路就是，根据我们想要的数据，全部查询出来，然后导出来，这个对数据量很大的时候会很慢，这里我提出来的思想就是分页和缓冲实现动态输出。

2.普通的我就不说了，下面我说一下分页和内存刷新思想。代码如下：

$conn = oci_connect('fin_data', 'fin_data', "(DEscriptION=(ADDRESS=(PROTOCOL =TCP)(HOST=192.168.6.65)(PORT = 1521))(CONNECT_DATA =(SID=hqygdw)))");

$sqlName = "select * 
from user_tab_columns 
where Table_Name='S_SALE_RECEIVABLE_DETAIL' 
order by column_name";

$filedName = oci_parse($conn, $sqlName);
oci_execute($filedName, OCI_DEFAULT); // 行数  OCI_DEFAULT表示不要自动commit

header('Content-Type: application/vnd.ms-excel;charset=gbk');
header('Content-Disposition: attachment;filename=test_' . time() . '.csv');
header('Cache-Control: max-age=0');

$fp = fopen('php://output', 'a');
$head = array();
$i = 0;
while ($row = oci_fetch_array($filedName, OCI_ASSOC + OCI_RETURN_NULLS)) {
    $head[$i] = iconv('utf-8', 'gbk', $row['COLUMN_NAME']);
    $i++;
}
fputcsv($fp, $head);

$selectCount = "select count(*)  as counts from S_SALE_RECEIVABLE_DETAIL t ";
$resultCount = oci_parse($conn, $selectCount); // 配置SQL语句，执行SQL
oci_execute($resultCount, OCI_DEFAULT); // 行数  OCI_DEFAULT表示不要自动commit
$count = oci_fetch_array($resultCount, OCI_ASSOC + OCI_RETURN_NULLS);

//$count['COUNTS']=10;
$pageNum = 50000;
$pagePre = ceil($count['COUNTS'] / $pageNum);
for ($i = 1; $i <= $pagePre; $i++) {
    $pageStart = ($i - 1) * $pageNum + $pageNum;
    $pageEnd = ($i - 1) * $pageNum;

    $select = "SELECT *
  FROM (SELECT A.*, ROWNUM RN
          FROM (SELECT * FROM S_SALE_RECEIVABLE_DETAIL) A
         WHERE ROWNUM <={$pageStart} )
 WHERE RN >= {$pageEnd}";

    $result = oci_parse($conn, $select); // 配置SQL语句，执行SQL
    oci_execute($result, OCI_DEFAULT); // 行数  OCI_DEFAULT表示不要自动commit
    $count =0;
    while ($rowResult = oci_fetch_array($result, OCI_ASSOC + OCI_RETURN_NULLS)) {
//        print_r(explode(',',$rowResult));exit;
        fputcsv($fp,$rowResult);
        $count++;
        if($count>=$pageNum){
            ob_flush();
            flush();
        }
    }
}

fputcsv($fp, $head);