为什么我得到允许的内存大小134217728字节耗尽错误

我只是在代码中找不到任何错误。CCD_ 1方法带来的问题（134217728字节的允许内存大小耗尽）。

代码：

<?php
    require "dbConnect.php";
    $username = $_POST['username'];
    if ($username != '') {
        $sql = "SELECT * FROM users WHERE username='$username'";
        $result = mysqli_query($con, $sql);
        $check = mysqli_fetch_array($result);
        $data = array();
        if (isset($check)) {
            echo "4";
            while ($row = mysqli_fetch_array($result)){
                echo "2";
                array_push ($data, array('name'=>$row[1], 'username'=>$row[2], 'password'=>$row[3], 'email'=>$row[4]));
            }
            echo json_encode(array("response"=>$data));
            mysqli_close($con);
        } else {
            echo "0";
        }
    } else {
        echo "3";
    }
?>

错误：

<br />
<b>Fatal error</b>:  Allowed memory size of 134217728 bytes exhausted (tried to allocate 64 bytes) in <b>/home/u766232015/public_html/phpScripts/getUSerData.php</b> on line <b>14</b><br />