php - PHP 5 中的输出缓冲和大型 MySQL 结果集

Question

我正在尝试从具有巨大表格(几乎有 4k 条记录)的数据库构建 XML 提要。我想使用输出缓冲让它吐出 XML，但脚本仍然超时。

ob_start();
$what = 'j.*, (select description from tb_job_type as jt WHERE jt.jobtype_id =  j.job_type_id) as job_type,';
$what .= '(select description from tb_location as l WHERE l.location_id = j.location_id) as location,';
$what .= '(select description from tb_industry as i WHERE i.industry_id = j.industry_id) as industry';
$where = ('' != $SelectedType) ?  'j.job_ad_type="' . $SelectedType .'"' : '';
$process = $db->executeQuery('SELECT ' . $what . ' FROM tb_job_ad as j' . $where);

while($result = mysql_fetch_array($process))
{
    $result['job_title_url']        = $form->urlString($result['job_title']);
    $result['job_title']            = htmlspecialchars($result['job_title'], ENT_QUOTES, 'UTF-8');
    $result['short_description']    = htmlspecialchars($result['short_description'], ENT_QUOTES, 'UTF-8');
    $result['full_description']     = htmlspecialchars($result['full_description'], ENT_QUOTES, 'UTF-8');
    $result['company_name']         = ucwords(strtolower($result['company_name']));
    $tpl->assignToBlock('ITEMS', $result);
}
$cheese = ob_get_contents();    
$actualize = $tpl->actualize('FEED');
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT" );
header("Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . "GMT" );
header("Cache-Control: no-cache, must-revalidate" );
header("Pragma: no-cache" );
header("Content-type: text/xml");
echo $actualize;
ob_flush();
print $cheese;
ob_end_clean();

这似乎是使脚本窒息的行:

$tpl->assignToBlock('ITEMS', $result);

请帮忙？

谢谢

米迪亚内。

Answer 1

会不会是你的查询比较慢？
比较

的输出

set_time_limit(60);
$process = $db->executeQuery('EXPLAIN SELECT ' . $what . ' FROM tb_job_ad as j' . $where);
while($result = mysql_fetch_array($process, MYSQL_ASSOC)) {
  echo join(' | ', $result), "<br />\n";
}

与Optimizing Queries with EXPLAIN .