分批批量导出百万条数据记录

/**
 * csv 批量导出
 * @param $mpid
 * @throws \think\db\exception\DataNotFoundException
 * @throws \think\db\exception\ModelNotFoundException
 * @throws \think\exception\DbException
 */
public function export($mpid)
{
    $wechat_mp_model = new WechatMp();

    $limit = 50000;//每次只从数据库取50000条以防变量缓存太大
    // buffer计数器
    $cnt = 0;

    $where['mpid'] = $mpid;
    $mpName = $wechat_mp_model->getCustomField($where, 'mpname');
    $start_time = $this->request->param('start_time', '');
    $end_time = $this->request->param('end_time', '');
    $args['start_time'] = $start_time;
    $args['end_time'] = $end_time;
    $xlsTitle = ['关注时间', '微信Openid', '微信昵称', '微信头像', '性别'];

    set_time_limit(0);

    $sqlCount = $this->get_fans_list($mpid, 0, $limit, $args, true);
    $fileName = iconv('utf-8', 'gb2312', $mpName);//文件名称
    $fileName = $fileName . date('_YmdHis');// 文件名称可根据自己情况设定
    // 输出Excel文件头，可把user.csv换成你要的文件名
    header('Content-Type: application/vnd.ms-excel;charset=utf-8');
    header('Content-Disposition: attachment;filename="' . $fileName . '"');
    header('Cache-Control: max-age=0');

    $fileNameArr = array();
    // 逐行取出数据，不浪费内存
    for ($i = 0; $i < ceil($sqlCount / $limit); $i++) { 

        $fp = fopen($fileName . '_' . $i . '.csv', 'w'); //生成临时文件 
        // chmod('attack_ip_info_' . $i . '.csv',777);//修改可执行权限 
        $fileNameArr[] = $fileName . '_' . $i . '.csv'; // 将数据通过fputcsv写到文件句柄 
        fputcsv($fp, $xlsTitle); 
        $start = $i * $limit; 
        $dataArr = $this->get_fans_list($mpid, $start, $limit, $args);
        foreach ($dataArr as $a) {
            $cnt++;
            if ($limit == $cnt) {
                //刷新一下输出buffer，防止由于数据过多造成问题
                ob_flush();
                flush();
                $cnt = 0;
            }
            fputcsv($fp, $a);
        }
        fclose($fp);  //每生成一个文件关闭
    }
    //进行多个文件压缩
    $zip = new \ZipArchive();
    $filename = $fileName . ".zip";
    $zip->open($filename, $zip::CREATE);   //打开压缩包
    foreach ($fileNameArr as $file) {
        $zip->addFile($file, basename($file));   //向压缩包中添加文件
    }
    $zip->close();  //关闭压缩包
    foreach ($fileNameArr as $file) {
        unlink($file); //删除csv临时文件
    }
    $this->insertLog($this->admin_id, '', '导出公众号粉丝');
    //输出压缩文件提供下载
    header("Cache-Control: max-age=0");
    header("Content-Description: File Transfer");
    header('Content-disposition: attachment; filename=' . basename($filename)); // 文件名
    header("Content-Type: application/zip"); // zip格式的
    header("Content-Transfer-Encoding: binary"); //
    header('Content-Length: ' . filesize($filename)); //
    @readfile($filename);//输出文件;
    unlink($filename); //删除压缩包临时文件
}