php 查看变量占据多少内存

memory_get_usage()   这个函数，获取当前使用内存量

echo '开始内存：'.memory_get_usage(), '';
$mysql_i=mysqli_connect('127.0.0.1:3306','root','root','online-txjp');
$res=$mysql_i->query("select id from ns_user_sanya_balance_log",MYSQLI_USE_RESULT);
$data=[];
while($row=$res->fetch_assoc()){
    array_push($data,$row['id']);
}

$data = implode(',',array_rand($data,10000));
$mysql_i->close();
unset($mysql_i);
unset($res);
$resdata=[];
$mysql_i=mysqli_connect('127.0.0.1:3306','root','root','online-txjp');
$results=$mysql_i->query("select * from ns_user_sanya_balance_log where id in ($data) ",MYSQLI_USE_RESULT);
if($results){
    while($rows=$results->fetch_assoc()){
        array_push($resdata,$rows);
    }
}


$mysql_i->close();
echo '运行后内存：'.round(memory_get_usage()/1024/1024, 2).'MB';
unset($data);
echo count($resdata);
unset($resdata);


echo '回到正常内存：'.round(memory_get_usage()/1024/1024, 2).'MB';

phpstrom 和vscode 开启debug模式的时候也都支持直接查看变量占用内存