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在執(zhí)行一個(gè)導(dǎo)出csv腳步時(shí),當(dāng)要導(dǎo)出的數(shù)據(jù)超過3w多條時(shí),就會(huì)報(bào)錯(cuò),如下:
Allowed memory size of 134217728 bytes exhausted (tried to allocate 20480 bytes)
php存儲3w多條數(shù)據(jù)這個(gè)數(shù)組占用內(nèi)存超過20M
解決方法:分批取數(shù)據(jù),分批處理數(shù)據(jù)
問題點(diǎn):一次取多少數(shù)據(jù)最合適
一次取1w條,減少數(shù)據(jù)庫IO操作次數(shù),但php數(shù)組就好較大
一次取1k條,增加了數(shù)據(jù)庫IO操作次數(shù),php數(shù)組很小
數(shù)據(jù)一共41000條
因?yàn)槭茄h(huán)查詢數(shù)據(jù),只能返回空,所以會(huì)有一次無效的IO查詢
每次請求次數(shù) | 響應(yīng)時(shí)間 | 數(shù)組庫IO次數(shù) |
---|---|---|
5000 | 11.34 | 10 |
1000 | 8.02 | 6 |
2000 | 7.07 | 4 |
3000 | 5.12 | 3 |
4000 | 4.93 | 3 |
綜合考慮,覺得使用每次請求1w條數(shù)據(jù)
代碼簡單記錄下
$filename = '測試';
$head = array('申請時(shí)間', '省', '市', '超市品牌');
$field = array('created_time', 'pro_name', 'city_name', 'brand_name');
$csv = ExportCsvService::getInstance(implode(",", $head), $field, $filename);
$param['limit'] = C('SQL_LIMIT');
$i = 0;
while (true) {
$param['current'] = $i + 1;
$info = $rainbowservice->get_list($param)['data']['list'];
if (empty($info)) {
$csv->end();
break;
} else {
$csv->sendDate($info);
}
unset($info);
$i++;
}
csv操作類
class ExportCsvService
{
private $content;
private $filename;
private $field;
private static $instance;
private function __construct($head,$field,$filename)
{
$this->field = $field;
$this->filename = $filename;
$this->content = iconv('UTF-8', 'GBK',$head) . PHP_EOL;
}
/**
* 實(shí)例化服務(wù)類
* @param $head
* @param $field
* @param $filename
* @return ExportCsvService
*/
public static function getInstance($head,$field,$filename) {
if (!self::$instance instanceof self) {
self::$instance = new self($head,$field,$filename);
}
return self::$instance;
}
/**
* 拼接要導(dǎo)出的數(shù)據(jù)
* @param $data
*/
public function sendDate($data) {
foreach ($data as $key => $value) {
$temp = [];
foreach ($this->field as $k) {
$temp[] = iconv('UTF-8', 'GBK', $value[$k]);
}
$this->content .= implode(",", $temp) . PHP_EOL; //用英文逗號分開
unset($temp);
}
}
/**
* 輸出數(shù)據(jù)
*/
public function end() {
header("Content-type:text/csv;charset=GBK");
header("Content-Disposition:attachment;filename=" . $this->filename);
header('Cache-Control:must-revalidate,post-check=0,pre-check=0');
header('Expires:0');
header('Pragma:public');
echo $this->content;
}
}
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