控制变量法-初中物理-Nobel Lecture, December 12, 1929-php执行SET GLOBAL connect_timeout=2效果

 1     $link = mysqli_connect("localhost", "wu", "wp", "wdb");
 2     $sql = ‘SET GLOBAL  connect_timeout=2‘;
 3     mysqli_query($link, $sql);
 4 
 5     ini_set(‘memory_limit‘, ‘-1‘);
 6     $sql =‘ww‘;
 7 $ww =0;
 8     if ($result = mysqli_query($link, $sql)) {
 9         while ($row = mysqli_fetch_assoc($result)) {
10             echo ‘<br>‘,$ww,‘--‘.time();
11             $ww++;
12         }
13         mysqli_free_result($result);
14     }
15 die();

 1     $link = mysqli_connect("localhost", "wu", "wp", "wdb");
 2     //$sql = ‘SET GLOBAL  connect_timeout=2‘;
 3     //mysqli_query($link, $sql);
 4 
 5     ini_set(‘memory_limit‘, ‘-1‘);
 6     $sql =‘ww‘;
 7 $ww =0;
 8     if ($result = mysqli_query($link, $sql)) {
 9         while ($row = mysqli_fetch_assoc($result)) {
10             echo ‘<br>‘,$ww,‘--‘.time();
11             $ww++;
12         }
13         mysqli_free_result($result);
14     }
15 die();

SHOW VARIABLES LIKE ‘%out%‘;

SET GLOBAL  connect_timeout=31536000;
SHOW VARIABLES LIKE ‘%out%‘;

SET GLOBAL  connect_timeout=2;
SHOW VARIABLES LIKE ‘%out%‘;