set_time_limit

(PHP 4, PHP 5, PHP 7)

set_time_limit — Limits the maximum execution time

Description

bool set_time_limit ( int $seconds )

Set the number of seconds a script is allowed to run. If this is reached, the script returns a fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value defined in the php.ini.

When called, set_time_limit() restarts the timeout counter from zero. In other words, if the timeout is the default 30 seconds, and 25 seconds into script execution a call such as set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out.

Parameters

seconds: The maximum execution time, in seconds. If set to zero, no time limit is imposed.

Return Values

Returns TRUE on success, or FALSE on failure.

Notes

Warning

This function has no effect when PHP is running in safe mode. There is no workaround other than turning off safe mode or changing the time limit in the php.ini.

Note:
The set_time_limit() function and the configuration directive max_execution_time only affect the execution time of the script itself. Any time spent on activity that happens outside the execution of the script such as system calls using system(), stream operations, database queries, etc. is not included when determining the maximum time that the script has been running. This is not true on Windows where the measured time is real.

User Contributed Notes

eric pecoraro at shepard com

10 years ago


I was having trouble with script timeouts in applications where the user prompted long running background actions. I wrote this cURL/CLI background script that solved the problem when making requests from HTTP.

<?php

/* BACKGROUND CLI 1.0
   
   eric pecoraro _at_ shepard dot com - 2005-06-02
   Use at your own risk. No warranties expressed or implied.

   Include this file at the top of any script to run it in the background
   with no time limitations ... e.g., include('background_cli.php');
   
   The script that calls this file should not return output to the browser. 
*/
#  REQUIREMENTS - cURL and CLI
   if ( !function_exists('curl_setopt') OR !function_exists('curl_setopt')  ) {
      echo 'Requires cURL and CLI installations.' ; exit ; 
   }
   
#  BUILD PATHS
   $script = array_pop(explode('/',$SCRIPT_NAME)) ; 
   $script_dir = substr($SCRIPT_NAME,0,strlen($SCRIPT_NAME)-strlen($script)) ;
   $scriptURL = 'http://'. $HTTP_HOST . $script_dir . "$script" ;
   $curlURL = 'http://'. $HTTP_HOST . $script_dir . "$script?runscript=curl" ;

#  Indicate that script is being called by CLI 
   if ( php_sapi_name() == 'cli' ) {
      $CLI = true ;
   }

#  Action if script is being called by cURL_prompt()
   if ( $runscript == 'curl' ) {
      $cmd = "/usr/local/bin/php ".$PATH_TRANSLATED ; // server location of script to run
      exec($cmd) ;
      exit;
   }

#  USER INTERFACE
   // User answer after submission.
   if ( $post ) {
      cURL_prompt($curlURL) ;
      echo '<div style="margin:25px;"><title>Background CLI</title>';
      echo 'O.K. If all goes well, <b>'.$script.'</b> is working hard in the background with no ' ;
      echo 'timeout limitations. <br><br><form action='.$scriptURL.' method=GET>' ;
      echo '<input type=submit value=" RESET BACKGROUND CLI "></form></div>' ;
      exit ;
   }
   // Start screen.
   if ( !$CLI AND !$runscript ) {
      echo '<title>Background CLI</title><div style="margin:25px;">' ;
      echo '<form action='.$scriptURL.' method=POST>' ;
      echo 'Click to run <b>'.$script.'</b> from the PHP CLI command line, in the background.<br><br>' ;
      echo '<input type=hidden value=1 name=post>' ;
      echo '<input type=submit value=" RUN IN BACKGROUND "></form></div>' ;
      exit ;
   }

#  cURL URL PROMPT FUNCTION
   function cURL_prompt($url_path) {
      ob_start(); // start output buffer
      $c=curl_init($url_path);
      curl_setopt($c, CURLOPT_TIMEOUT, 2); // drop connection after 2 seconds
      curl_exec($c);
      curl_close($c);
      ob_end_clean(); // discard output buffer
   }
?>

kexianbin at diyism dot com

1 year ago


Both set_time_limit(...) and  ini_set('max_execution_time',...); won't count the time cost of sleep,file_get_contents,shell_exec,mysql_query etc, so i build this function my_background_exec(), to run static method/function in background/detached process and time is out kill it:

my_exec.php:
<?php
function my_background_exec($function_name, $params, $str_requires, $timeout=600)
         {$map=array('"'=>'\"', '$'=>'\$', '`'=>'\`', '\\'=>'\\\\', '!'=>'\!');
          $str_requires=strtr($str_requires, $map);
          $path_run=dirname($_SERVER['SCRIPT_FILENAME']);
          $my_target_exec="/usr/bin/php -r \"chdir('{$path_run}');{$str_requires} \\\$params=json_decode(file_get_contents('php://stdin'),true);call_user_func_array('{$function_name}', \\\$params);\"";
          $my_target_exec=strtr(strtr($my_target_exec, $map), $map);
          $my_background_exec="(/usr/bin/php -r \"chdir('{$path_run}');{$str_requires} my_timeout_exec(\\\"{$my_target_exec}\\\", file_get_contents('php://stdin'), {$timeout});\" <&3 &) 3<&0";//php by default use "sh", and "sh" don't support "<&0"
          my_timeout_exec($my_background_exec, json_encode($params), 2);
         }

function my_timeout_exec($cmd, $stdin='', $timeout)
         {$start=time();
          $stdout='';
          $stderr='';
          //file_put_contents('debug.txt', time().':cmd:'.$cmd."\n", FILE_APPEND);
          //file_put_contents('debug.txt', time().':stdin:'.$stdin."\n", FILE_APPEND);

          $process=proc_open($cmd, [['pipe', 'r'], ['pipe', 'w'], ['pipe', 'w']], $pipes);
          if (!is_resource($process))
             {return array('return'=>'1', 'stdout'=>$stdout, 'stderr'=>$stderr);
             }
          $status=proc_get_status($process);
          posix_setpgid($status['pid'], $status['pid']);    //seperate pgid(process group id) from parent's pgid

          stream_set_blocking($pipes[0], 0);
          stream_set_blocking($pipes[1], 0);
          stream_set_blocking($pipes[2], 0);
          fwrite($pipes[0], $stdin);
          fclose($pipes[0]);

          while (1)
                {$stdout.=stream_get_contents($pipes[1]);
                 $stderr.=stream_get_contents($pipes[2]);

                 if (time()-$start>$timeout)
                    {//proc_terminate($process, 9);    //only terminate subprocess, won't terminate sub-subprocess
                     posix_kill(-$status['pid'], 9);    //sends SIGKILL to all processes inside group(negative means GPID, all subprocesses share the top process group, except nested my_timeout_exec)
                     //file_put_contents('debug.txt', time().":kill group {$status['pid']}\n", FILE_APPEND);
                     return array('return'=>'1', 'stdout'=>$stdout, 'stderr'=>$stderr);
                    }

                 $status=proc_get_status($process);
                 //file_put_contents('debug.txt', time().':status:'.var_export($status, true)."\n";
                 if (!$status['running'])
                    {fclose($pipes[1]);
                     fclose($pipes[2]);
                     proc_close($process);
                     return $status['exitcode'];
                    }

                 usleep(100000); 
                }
         }
?>

a_class.php:
<?php
class A
{
    static function jack($a, $b)
           {sleep(4);
            file_put_contents('debug.txt', time().":A::jack:".$a.' '.$b."\n", FILE_APPEND);
            sleep(15);
           }
}
?>

test.php:
<?php
require 'my_exec.php';

my_background_exec('A::jack', array('hello', 'jack'), 'require "my_exec.php";require "a_class.php";', 8);
?>

mba_aslam at yahoo dot com

9 years ago


while setting the set_time_limit(), the duration of sleep() will be ignored in the execution time. The following illustrates:

<?php

set_time_limit(20);

while ($i<=10)
{
        echo "i=$i ";
        sleep(100);
        $i++;
}

?>

Output:
i=0 i=1 i=2 i=3 i=4 i=5 i=6 i=7 i=8 i=9 i=10

php at mightycpa.com

12 years ago


You may also need to look at Apache's timeout setting (Win32 version for me), I changed max execution time value in php.ini, and still got stopped by Apache's timeout value in the httpd.conf file.

cweiske at cweiske dot de

7 years ago


To get the currently used time, use getrusage()

AtlantisNet

7 years ago


In IIS, there is another global timeout setting which will override any PHP settings.  You can alter this timeout by following the following instructions:

http://www.iisadmin.co.uk/?p=7

jonathon dot keogh at gmail dot com

7 years ago


You can do set_time_limit(0); so that the script will run forever - however this is not recommended and your web server might catch you out with an imposed HTTP timeout (usually around 5 minutes).

You should check your web server's guides for more information about HTTP timeouts.

Jonathon

rsallo at gna dot NOSPAM dot es

12 years ago


When you are working with IIS, PHP timeout is valid only when it's lower than script timeout defined by IIS.

IIS 5 has a default timeout of 300 seconds. If you need a higher timeout, you also have to change IIS properties. Otherwise, your server will stop your PHP script before it reaches its own timeout.

f.nakamura

9 months ago


set_tme_limit resets the execution time count.

test code1:
<?php
echo '<html><body>';
set_time_limit(1);
$i = 0;
while(++$i < 100000001){
        if($i % 100000 == 0){
                echo $i / 100000, "<br/>\n";
        }
}
echo "done.<br/>\n";

// will not echo 'done.'.
?>

test code2:
<?php
echo '<html><body>';
set_time_limit(1);
$i = 0;
while(++$i < 100000001){
        if($i % 100000 == 0){
                set_time_limit(1);
                echo $i / 100000, "<br/>\n";
        }
}
echo "done.<br/>\n";

// will echo 'done.'
?>

robertbrogers at gmail dot com

2 years ago


Documentation states:
When called, set_time_limit() restarts the timeout counter from zero. In other words, if the timeout is the default 30 seconds, and 25 seconds into script execution a call such as set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out.

If I have a long running script and i want a exact  time limit, I set this as near as possible to the first line.

php at stock-consulting dot com

9 years ago


To find out the currently set time limit, use



<?php

 ini_get('max_execution_time');

?>



If set_time_limit has been previously called in the script, the result will be the value which was passed to set_time_limit (and not, as the function name "ini_get" appears to suggest, the value from the php.ini file).

rycardo74 at gmail dot com

10 years ago


this work to fine html streaming AND time pass limit



<?php

header('Content-type: text/plain');

echo date("H:m:s"), "\n";

set_time_limit(30);

for ($i = 0; $i < 1000; $i++)

{



    echo date("H:m:s"),"\n";

    for ($r = 0; $r < 100000; $r++){

    $X.=  tan(M_LNPI+log(ceil(  date("s")*M_PI*M_LNPI+100)));

    }

    ob_flush();   

    flush();



}

echo "work! $x";

?>

alexander dot krause at ed-solutions dot de

4 years ago


A nice workaround to have a real max_execution_time (needs posix and pcntl):



<?php

$pid=pcntl_fork();



if ($pid) {

  //long time process

  $a=0;

  while (true) {

    echo "a=$a\n\n";

    ob_flush();

    flush();

    $a++;

    shell_exec('sleep 10&');

  }

} else {

  //time-limit checker

  sleep(5);

  posix_kill(posix_getppid(),SIGKILL);

}

?>

jatin at jatinchimote dot com

10 years ago


If you set the number of seconds to a very large number (not many ppl do that, but just in case) then php exits with a fatal error like :



Fatal error: Maximum execution time of 1 second exceeded in /path/to/your/script/why.php



[EDIT by danbrown AT php DOT net: This is due to the limit of 32-bit signed integers.]

Silver_Knight

6 years ago


if you are running a script that needs to execute for unknown time, or forever.. you may use
set_time_limit(0);
.....
...
..
.
and at the end of the script use flush() function to tell phpto send out what it has generated.

ratty at brohoof dot com

4 years ago


One thing that I wish I had found sooner is, if you're using php-cli and really need to limit the executation time, and if you're in *nix, you can use "timeout" which is part of coreutils.
For example:

timeout 5 /usr/bin/php -q /path/to/script

and it will kill it if it takes longer than 5 seconds.
I had a few quick php scripts I wrote for use with cacti for example.

konrads dot smelkovs at gmail dot com

10 years ago


If you are streaming large data from database, it is counted towards the max exec time.

bjfieldNO at SPAMgmail dot com

9 years ago


Timeouts after five minutes in IIS on Windows are caused by an inherited CGI Timeout value of 300 seconds.  This is not a PHP problem.  The fix is to add custom values for the files or directories that need longer to run.

In IIS 5.0 or 7.0 (beta as of this note), you can change this value on a fairly granular level using IIS Manager, under (roughly) YOURSITE -> Properties -> Home Directory -> Configuration (button) -> Options, but in IIS 6.0, this functionality is turned off (!), so you have to get into the Metabase.

Find the site number in Metabase Explorer (e.g., 12345678), then from CMD prompt:

[get to the scripts dir]
cd C:\Inetpub\AdminScripts

[this for each subdirectory from off the site root]
cscript adsutil.vbs CREATE W3SVC/12345678/root/"MY SUBDIRECTORY" IIsWebDirectory

[this for the file in question]
cscript adsutil.vbs CREATE W3SVC/12345678/root/"MY SUBDIRECTORY"/ILikeToTimeOut.php IIsWebFile

[this to set the timeout]
cscript adsutil.vbs set W3SVC/12345678/root/"MY SUBDIRECTORY"/ILikeToTimeOut.php/CGITimeout "7200"

Note:  "7200" is 2 hours in seconds, but can be whatever.

I derived the solution above from this fine article:
http://www.iis-resources.com/modules/AMS/article.php?
storyid=509&page=3

Cleverduck

10 years ago


Regarding what 'nytshadow' said, it's important to realize that max-execution-time and the set_time_limit functions measure the time that the CPU is working on the script.  If the script blocks, IE: for input, select, sleep, etc., then the time between blocking and returning is NOT measured.  This is the same when running scripts from the command line interface.  So if you've got a log parser written in PHP that tails a file, that program WILL fail eventually.  It just depends how long it takes to read in enough input to process for 30 seconds.

If you're writing a command line script that should run infinitely, setting max-execution-time to 0 (never stop) is HIGHLY recommended.

ravenswd at gmail dot com

6 years ago


Unfortunately, a script which gets into an infinite loop can produce an alarming amount of output in only a few seconds. I was attempting to debug a script, and I added

<?php
set_time_limit(2);
?>

to the beginning of the script. Unfortunately, even two seconds of run time produced enough output to overload the memory available to my browser.

So, I wrote a short routine which would limit the execution time, and also limit the amount of output returned. I added this to the beginning of my script and it worked perfectly:

<?php
set_time_limit(2);

ob_start();     // buffer output

function shutdown () {
    // print only first 2000 characters of output
    $out = ob_get_clean();
    print substr($out, 0, 2000);
}

register_shutdown_function('shutdown');
?>

6 years ago


If you use Apache you can change maximum execution time by .htaccess with this line

php_value max_execution_time 200

mingalevme at gmail dot com

3 years ago


If you're using PHP_CLI SAPI and getting error "Maximum execution time of N seconds exceeded" where N is an integer value, try to call set_time_limit(0) every M seconds or every iteration. For example:

<?php

require_once('db.php');

$stmt = $db->query($sql);

while ($row = $stmt->fetchRow()) {
    set_time_limit(0);
    // your code here
}

?>

agvozden at gmail dot com

5 years ago


If you got something like:



msg: set_time_limit() [function.set-time-limit]: Cannot set time limit in safe mode 



try this:



<?php

        if( !ini_get('safe_mode') ){

            set_time_limit(25);

        }

?>

set_time_limit

Description

Parameters

Return Values

Notes

See Also

User Contributed Notes