PHP - Considerable Performance Drop After Sleep Is Introduced

Well PHP manual says that the script execution will be delayed by $x seconds if you write a codes like this:

Code: [Select]
$x = 5; //5 secs
sleep($x);

Now I have this script in which I write the four lines to the screen one by one, each should be delayed by 5 secs after the last line is output to the screen. It does not work out at all...

Code: [Select]
echo "Update setting 1:";
sleep(5);
echo "Success! <br>Updating setting 2";
sleep(5);
echo "Success! <br>Updating setting 3";
sleep(5);
echo "Success! <br>Updating setting 4";

Instead, the entire script execution is delayed by 15 secs, with all four lines output at the same time. Why is this happening? Is there a way to fix it? Please help...

Hi,

I am trying to loop a script every 10 seconds but am getting the following error:

Fatal error: Maximum execution time of 60 seconds exceeded

Part of the code is:


<?php

while (1)
{
echo "hello";
sleep(10);
ob_flush;
flush();
}
?>


I have put echo "hello" just to test before adding the script.

Is there a correct way to do this loop? also running this the page struggles and says it is still loading.

I want the login script to echo out a statement, and then after 5 seconds (if the user hasn't clicked the link manually) I want it to redirect with the header redirect. I'm using the sleep function for the delay of the redirect. Here's the concerned portion of the login script:

// check to see if the INPUT DATA matches the DATABASE COLUMNS!

if ($nickname == $dbuser_name && sha1($password) == $dbuser_password) {

// set a session after login

$_SESSION['user_name'] = $dbuser_name;

$_SESSION['user_id'] = $dbuser_id;

echo "<center>You're logged in! 

<a href='01.php'>Click here</a> to go to the main page.</center>";

sleep(5); // seconds to wait

header ('Location: 01.php');

// password incorrect error message

} else {

echo "<center>Incorrect password!</center>";

}


But the echo statement never gets printed out, any idea why it gets swallowed by the sleep function?

Im going to use a large array of arrays, each of one having a lot of values and some sub arrays. My question is...  is faster to use arrays or is better to have a object to acces using methods and all? i suppose objects are slower...

Also i was planing in use arrays with string keys in nearly all places, normally these are slower, but in php hashes and arrays are the same tipe  so i dont know...

A few questions that if I was more knowledgeable about MySQL (such as the query log that I've heard of).
 - Does mysqli::multi_query() make multiple requests to the server or just one?
 - If it is just splitting the queries on the semicolon and then making multiple requests, is it still faster than looping and querying in PHP?
 - Does it take less memory than, lets say, mysql_query() foreach query?
 - Is it faster than, lets say again, mysql_query() looped?

The last 2 I can probably just benchmark myself but I'm hoping someone will know off had.

Background (blah blah blah)
I'm working on a lean rapid development framework for myself (and maybe others eventually) to use. Much like Cake and other frameworks it does a lot of queries, often times more then you need. The sacrifice of course is performance VS ease of development, but I'm trying to not make a martyr out of my framework :-)

I've observed on many occasions that simple queries can take more time than a complex query  on seemingly random occasions. My understanding is that this is because of the connection, not the real amount of time it took for the server to query. I figure if I avoid multiple requests to the server I will cut down on the time everything takes. My theory is based on the same concept of combining all your CSS and JS files into single files to avoid dozens of HTTP requests which slow down page load time.

I am wondering since in php when you write string in " " quotes php will look if there is any variable and if it is it will read that variable and replace variable name with that value inside the string. However when i use ' ' quotes php will not look for any variables inside that string. So my question is when you write a really big application is it good to always use ' '  quotes when you can instead of " " ones. Does that have an impact on performance. Thanks

I am very new to PHP and have tried various techniques but I am getting a 500 error when clicking on the export button to download a csv report. I'm not sure why the previous developer did it this way.

Is there a better why in PHP to make this code better? Willing to understand and learn from an PHP expert.

The database is MYSQL.

            $coursefilterid = $_GET['course'];

            $conn = new mysqli($host, $username, $password, $database);
            if ($conn->connect_error) {
                die("Connection failed: " . $conn->connect_error);
            }

            $sqluserenrolled = "select mdl_user.username, mdl_user_enrolments.userid as enrolleduserid, mdl_enrol.courseid from mdl_user_enrolments
    Inner Join
    mdl_enrol
    on 
    mdl_enrol.id = mdl_user_enrolments.enrolid
    Inner Join
    mdl_user
    on
    mdl_user.id = mdl_user_enrolments.userid
    where  
    mdl_enrol.courseid = '" . $coursefilterid . "'
    order by mdl_user.username
    
    ";

            $queryenrolleduser = mysqli_query($conn, $sqluserenrolled);

            ?>

<html>
<head>
</head>
<body>

    <form method="post"
        action="<?php echo "userlistssiexport.php?id=$coursefilterid"?>">
        <input type="hidden" name="exportcourseid"
            value="<?php echo $coursefilterid;?>"> <input type="hidden"
            name="sessid" value="<?php echo $USER->sesskey;?>"> <input
            class="btn btn-primary" type="submit" name="submit"
            value="<?php echo "Export";?>">
    </form>


<?php
            $noteid = "";
            $cmId = "";
            ?>
          
    <table class="data-table">
        <caption class="title">User info</caption>
        <thead>
            <tr>
                <th>Username</th>
                <th>Firstname</th>
                <th>Lastname</th>
                <th>Email</th>
                <th>Last login</th>
                <th>Createddate</th>
                <th>Position</th>
                <th>Organization</th>
                <th>Certificate Request Date</th>
                <th>Role1</th>
                <th>Role2</th>
                <th>Role3</th>
            </tr>
        </thead>
        <tbody>

    <?php

            while ($row = mysqli_fetch_array($queryenrolleduser)) {

                $enrolleduserid = $row['enrolleduserid'];

                $sql = "select mdl_user.username as username, 
        mdl_user.firstname as firstname,
        mdl_user.lastname as lastname,
        mdl_user.email as email,
       mdl_user.lastlogin as lastaccess,
        mdl_user.timecreated as createddate,
        mdl_user_info_data.data as position 
        
        
        from mdl_user
        Inner Join 
        mdl_user_info_data
        on
        mdl_user_info_data.userid = mdl_user.id
        Inner Join
        mdl_user_info_field
        on 
        mdl_user_info_field.id = mdl_user_info_data.fieldid
        Inner Join
        mdl_user_lastaccess
        on
        mdl_user_lastaccess.userid = mdl_user.id
        
        
        where  mdl_user_info_field.id = 1
        and
        mdl_user.deleted = 0
        and
        mdl_user.id = '" . $enrolleduserid . "'
        group by mdl_user.username
        order by mdl_user.username
    
        ";
                $query = mysqli_query($conn, $sql);

                if (! $query) {
                    die('SQL Error: ' . mysqli_error($conn));
                } else {}

                ?>

        <?php
                $no = 1;
                $total = 0;
                $username = '';
                $coursename = '';
                $content = '';
                $modulename = '';
                $organization = '';
                $userid = '';
                $certificatedate = '';
                $userrole = '';
                $enrolleduserid = '';

                while ($row = mysqli_fetch_array($query)) {
                    // Do something here
                    $username = $row['username'];
                    $coursename = $row['coursename'];
                    $content = $row['content'];
                    $noteid = $row['noteid'];
                    // $notedatetime = date("d/m/y g:i (A)", $row['notedate']);
                    $notedatetime = date("D M j Y G:i A", $row['notedate']);
                    $lastaccess = date("D M j Y G:i A", $row['lastaccess']);
                    $createddate = date("D M j Y G:i A", $row['createddate']);
                    $datafile = $username . $coursename . $content;

                    echo '<tr>      
                    <td>' . $row['username'] . '</td>
                    <td>' . $row['firstname'] . '</td>
                    <td>' . $row['lastname'] . '</td>
                    <td>' . $row['email'] . '</td>                          
                    <td>' . $lastaccess . '</td>                                    
                    <td>' . $createddate . '</td>   
                    <td>' . $row['position'] . '</td>    
                                                    
                ';
                    $modid = $row['contextid'];
                    // Get module name

                    $sqlmodule = "select mdl_user.username as username, 
        mdl_user.firstname as firstname,
        mdl_user.lastname as lastname,
        mdl_user.email as email,
        FROM_UNIXTIME(mdl_user_lastaccess.timeaccess) as lastaccess,
        FROM_UNIXTIME(mdl_user.timecreated) as createddate,
        mdl_user_info_data.data as organization 
        
        
        from mdl_user
        Inner Join 
        mdl_user_info_data
        on
        mdl_user_info_data.userid = mdl_user.id
        Inner Join
        mdl_user_info_field
        on 
        mdl_user_info_field.id = mdl_user_info_data.fieldid
        Inner Join
        mdl_user_lastaccess
        on
        mdl_user_lastaccess.userid = mdl_user.id
        
        
        where  mdl_user_info_field.id = 3
        and
        mdl_user.deleted = 0
        and
        mdl_user.username ='" . $username . "'";

                    $querymodule = mysqli_query($conn, $sqlmodule);
                    ?>              
            <?php
                    $modulenamelink = "";
                    while ($row = mysqli_fetch_array($querymodule)) {

                        $organization = $row['organization'];
                    }

                    echo '<td>' . $organization . '</td>';

                    $sqlCertificateDateuid = "select id from mdl_user where username = '" . $username . "'";

                    $queryCertificateDateuid = mysqli_query($conn, $sqlCertificateDateuid);
                    while ($row = mysqli_fetch_array($queryCertificateDateuid)) {

                        $userid = $row['id'];
                    }

                    $sqlcertificatedate = "select * from mdl_certificateemail where userid = '" . $userid . "'
        and courseid = '" . $coursefilterid . "'";

                    $querycertificaterequestdate = mysqli_query($conn, $sqlcertificatedate);
                    while ($row = mysqli_fetch_array($querycertificaterequestdate)) {

                         $certificatedate = date("D M j Y g:i:s A", $row['unixdatetimecertificate']);
                    }
                    echo '<td>' . $certificatedate . '</td>';

                    $sqluserrole = "select mdl_role_assignments.userid, mdl_role_assignments.roleid,mdl_course_modules.course, mdl_role.shortname as rolename,FROM_UNIXTIME(mdl_role_assignments.timemodified)  from mdl_role_assignments 
        Inner Join
        mdl_context
        on
        mdl_context.id = mdl_role_assignments.contextid
        Inner Join
        mdl_course_modules
        on 
        mdl_course_modules.instance = mdl_context.instanceid
        Inner Join
        mdl_role
        on 
        mdl_role.id = mdl_role_assignments.roleid
        
        where mdl_course_modules.course = '" . $coursefilterid . "'
        and
        mdl_role_assignments.userid = '" . $userid . "'
        group by
        mdl_role_assignments.userid,
        mdl_role_assignments.roleid,
        mdl_course_modules.course,
        mdl_role.shortname,
        mdl_role_assignments.timemodified
        
        order by mdl_role_assignments.timemodified
        ";

                    $userlistrole = '';
                    $queryuserrole = mysqli_query($conn, $sqluserrole);
                    while ($row = mysqli_fetch_array($queryuserrole)) {

                        $userrole = $row['rolename'];
                        $userlistrole = array(
                            array(
                                $userrole
                            )
                        );
                        // echo '<td>'.$userrole.'</td>';
                    }

                    foreach ($userlistrole as $listrole) {

                        // echo $listrole;
                    }

                    $teacherrole = array(
                        'student'
                    );
                    foreach ($teacherrole as $rolename) {
                        $role = $DB->get_record('role', array(
                            'shortname' => $rolename
                        ));
                        $context = get_context_instance(CONTEXT_COURSE, $coursefilterid);
                        // $context = context_course::instance($cid1);
                        $teachers = get_role_users($role->id, $context);

                        foreach ($teachers as $teacher) {

                            $teacherid = $teacher->id;
                            if ($teacherid == $userid) {
                                echo '<td>student</td>';
                            }
                        }
                    }

                    $teacherrole = array(
                        'editingteacher'
                    );
                    foreach ($teacherrole as $rolename) {
                        $role = $DB->get_record('role', array(
                            'shortname' => $rolename
                        ));
                        $context = get_context_instance(CONTEXT_COURSE, $coursefilterid);
                        // $context = context_course::instance($cid1);
                        $teachers = get_role_users($role->id, $context);

                        foreach ($teachers as $teacher) {

                            $teacherid = $teacher->id;
                            if ($teacherid == $userid) {
                                echo '<td></td>';
                                echo '<td>editingteacher</td>';
                            }
                        }
                    }

                    $teacherrole = array(
                        'manager'
                    );
                    foreach ($teacherrole as $rolename) {
                        $role = $DB->get_record('role', array(
                            'shortname' => $rolename
                        ));
                        $context = get_context_instance(CONTEXT_COURSE, $coursefilterid);
                        // $context = context_course::instance($cid1);
                        $teachers = get_role_users($role->id, $context);

                        foreach ($teachers as $teacher) {

                            $teacherid = $teacher->id;
                            if ($teacherid == $userid) {
                                echo '<td>manager</td>';
                            }
                        }
                    }
                    echo '</tr>';
                }
            }

            ?>

    
        </tbody>
        <tfoot>

        </tfoot>
    </table>
</body>
</html>

<?php
    }
}

else {
    header("Location:/index.php");
    // echo "something";
    die();
}
}

else {

header("Location:/index.php");
die();

}

?>

 

I want to do a test while refreshing the page 100 times with 500 rows in a table, and then without 500 rows in a table and with different kind of php code, i need to do some type of testing to get results back in to show which way is faster for mysql/php.

Any idea how to do this any scripts out there or a built in php/mysql function?

Thanks

Alright guys, I see people recommending prepared statements (PDO/MySQLi) and saying that they are way to go these days.

However upon doing a bit more research, I've found that prepared statements, PDO in particular, is lacking in terms of performance, especially using SELECT statements. 

Now I'm starting a new project, which is basically a text based game with lots of queries and DB interaction, so I'm really interested in knowing what's the best approach for me.  I was leaning towards PDO but I don't want it crawling my server under heavy load.

I appreciate any advices or first hand experiences on this.

I have the following simple code to test against collision on a primary key I am creating:

Code: [Select]
        $machine_ids = array();
for($i = 0; $i < 100000; $i++) {
//Generate machine id returns a 15 character alphanumeric string
                $mid = Functions::generate_machine_id();

if(in_array($mid, $machine_ids)) {
die("Collision!");
} else {
$machine_ids[] = $mid;
}
}

die("Success!");

Any idea why this is taking minutes to run? Anyway to speed it up?

Do I really have to care about the amount of spaces/tabs I have in my program?

Is my code good? Example:

Code: [Select]


class SportListout{

public $start;
public $db;
private $junk = 'This is junk data. Unable to find it \'s parents. It is recommended that you delete this data.';

function __construct($db){
$this -> db = $db;
$this -> setStartingParent();
}

function searchListout($sp){
$notif = 'There are no search results that match that criteria.';
if(strlen($sp) > 0){
if(strlen($sp) < 3){


This is my common text format. Is this ok or should I not make spaces in between functions?

Hello,   Any ideas why server resources not exhausted on the code below, when my.cnf and php.ini are both set to use half the resources each? PHP & MySQL will both utilize all allotted resources on other scripts, so it's not a tuning problem. There is no script-side tuning.   The bottleneck: pdo select as shown below

foreach($bigList as $listObject) {
                $sql = $dbl->prepare("SELECT * FROM fewMillionRows WHERE indexedCol1=:indexedCol1 AND indexedCol2=:indexedCol2 AND indexedCol3=:indexedCol3 AND indexedCol4=:indexedCol4 LIMIT 1");
                $sql->execute($preparedValues);
                $return = $sql->fetchAll(PDO::FETCH_ASSOC);
}

On a dedicated server with 8GB RAM, the server uses >5% cpu/ram but takes a long time to finish the script.     Second Question What are some alternative designs?   Because the column values all happen to be alphanumeric, I could select the entire table and store it in an array. Accessing the keys like so: indexedCol1indexedCol2indexedCol3indexedCol4.   Results: MyISAM - Select Whole Table: 30 seconds MyISAM – Select Individual Rows (10k times) – 68 seconds InnoDB – Select Whole Table: 30 seconds InnoDB – Select Individual Rows (10k times) – 131 seconds     I am surprised it takes so long to select a whole table. The server resources use 1% for about 20 seconds, then cpu/ram jump to 30%+ for about 10 seconds. This is still drastically faster than individual selects.   In this instance, $bigList is over 500k items. At 68 seconds per 10k rows it’s absurdly long. Building an array with key/values is the only realistic way I currently know of, but I suspect there is a much better way of doing this.     As far as I know, I cannot do a select like so: SELECT * FROM t1 WHERE (column1,column2,column3) IN  ((val1, val2,val3), (val4, val5,val6)) There is no way to determine whether a row was found for each entry as far as I know. 

Hi All,

I have written the following to validate my dynamic includes, one question is i will be using sessions to control user access to certain pages. Obviously the session_start() has to go into my index.php file. Can anyone see any problems with this or my dynamic include validation code. My page varilable is populated using the mod_rewirte function in appache.

<?PHP 
include('inc/settings.inc.php');
if(isset($_GET['page'])) {
//remove slashes
$page = stripslashes($_GET['page']);
//rebuild the extension and file name
$filename = 'lib/'.$page.'.php';
//Check to see if the file exists in lib
if (file_exists($filename)) {
//Dynamic Switch
$allowed = array(  array("test", "New Customers"),
array("home", "Home Page"),
);
$iffed = false;
$get_section = $_GET['page'];
//Create a dynamic switch to check for files being in my allowed array
foreach($allowed as $rd) {
if($get_section == $rd[0]) {
$iffed = $rd;
$content = $filename;
foreach($rd as $value) {
$page_title = $value;
}
}
}
if($iffed === false) {
//File is not in my include list.
die( "Page does not pass the validated inclusion list." );
}
} else {
//Page does not exist in my lib folder.
die('Page does not exist, please contact the administrator.');
}
} else {
// If no page is requested then default home.
$filename = 'lib/home.php';
$content = '1';
$page_title = 'Home';
}
?>

Thanks in advance.

Sam

I can't figure out how to optimize my Zend framework performance.  My query executes in 200ms but my page is taking almost 60 seconds to load.  While checking the zend toolbar it shows that my page size is 14mb and I don't know why.  The routes and options size is really large but I don't know what is causing this.  Any ideas?   To see the full breakdown: http://awesomescreen....com/0c73vewycc    

Is there a performance or security issue when embedding HTML code to be written to a page using a series of ECHO statements within PHP?

Here's two examples:

<?php
// Some PHP code
echo "<p>Hello, World</p>\n";
// More php code
?>

versus:

<?php>
// Some PHP script commands
?>
<p>Hello World\n";
<?php
// More PHP code
?>

Is there a performance issue or potential security flaw that would make the first example any worse/better than the second?
(Is one method more "secure" than the other method, I guess is what I'm asking?)

I like the ease of just throwing in HTML within a PHP script without having toe escape quote marks, etc.  But, I'm a bit concerned about security since whatever technique I use will be incorporated into a "commercial" production website.