PHP Warning: exec(): Unable to fork [rm some_file.txt] in some.php on
line 111
There is a question that has been asked before about this subject PHP Warning: exec() unable to fork I have similar problem but it not the same.
ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 31364
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 31364
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
My limits are shown above and it looks like there is nothing with low limit on server that can affect this error.
I tried to unsetting variables after using them both with unset and by setting them to null to free up memory. But it has no effect.
unset($var);
$var = null;
Unable to fork error occuring because of exhausting of some resources but I can't find the reason. Can you suggest me to which logs I should look?
Any ideas or workaround for this problem?
Any ideas or workaround for this problem?
The problem is likely a flaw in your code - like it was in https://stackoverflow.com/a/20649541/2038383. So the work around is fixing it.
Can you suggest to me in which logs I should look?
There is your PHP logs, then your system / kernel logs.
You already know where to get the PHP log and what is in it by default. Unfortunately your not going to get much more out of PHP. You could catch the error yourself with set_error_handler() but that won't give you any more useful info (it'll give you PHP's "errno" but not UNIX's errno).
As for system logs; I said in comments check your syslog. There might be something in there, and it's always a good starting point. But actually you won't generally see ulimit violations in syslog. Some will get logged (example stack size generates segfault which gets logged) but many won't. This post deals with how to get logs of ulimit violations: https://unix.stackexchange.com/questions/139011/how-do-i-configure-logging-for-ulimits. Surprisingly non trivial.
The way system ulimit violations are supposed to be reported by system call is by setting an errno. For example, if max user processes is hit fork() will return EAGAIN.
So ... you need to get at that UNIX errno to know what is really going on. Unfortunately I don't think there is a way in PHP (there is posix_errno(), but pretty sure that is limited to PHP's posix_XXX function library). Also note, it's PHP generating the "Unable to fork" message. How that maps to actual system call error is not completely transparent.
So best off looking at other ways to debug of which there are plenty. Like system monitoring tools: ps, dstat, strace might be a good start.
After installing APC, see the apc.php script, the uptime restart every one or two hours? why?
How can I change that?
I set apc.gc_ttl = 0
APC caches lives as long as their hosting process, it could be that your apache workers reach their MaxConnectionsPerChild limit and they get killed and respawned clearing the cache with it. This a safety mechanism against leaking processes.
mod_php: MaxConnectionsPerChild
mod_fcgid or other fastcgi: FcgidMaxRequestsPerProcess and PHP_FCGI_MAX_REQUESTS (enviroment variable, the example is for lighttpd but it should be considered everywhere php -b used)
php-fpm: pm.max_requests individually for every pool.
You could try setting the option you are using to it's "doesn't matter" value (usually 0) and run test the setup with a simple hello world php script, and apachebench ab2 -n 10000 -c 10 http://localhost/hello.php (tweak the values as needed) to see if the worker pid's are changing or not.
If you use a TTL of 0 APC will clear all cache slots when it runs out of memory. This is what appends every 2 hours.
TTL must never be set to 0
Just read the manual to understand how TTL is used : http://www.php.net/manual/en/apc.configuration.php#ini.apc.ttl
Use apc.php from http://pecl.php.net/get/APC, copy it to your webserver to check memory usage.
You must allow enough memory so APC have 20% free after some hours running. Check this on a regular basis.
If you don't have enough memory available, use filters option to prevent rarely accessed files from being cached.
Check my answer there
What is causing "Unable to allocate memory for pool" in PHP?
I ran into the same issue today, found the solution here:
http://www.itofy.com/linux/cpanel/apc-cache-reset-every-2-hours/
You need to go to AccesWHM > Apache Configuration > Piped Log Configuration and Enable Piped Apache Logs.
I have a PHP script that when called via a browser it times-out after exactly 60 seconds. I have modified httpd.conf and set the Timeout directive to be 300. I have modified all PHP timeout settings to extend longer than 60 seconds. When I run the script from the command line it will complete. When I execute through browser each time after 60 seconds, POOF, timeout.
I have also checked for the existence of timeout directives in any of the .htaccess files. Nothing there.. I am completely stumped.
I am also forcing set_time_limit(0) within the PHP code.
I've been digging and testing for a week and have exhausted my knowledge. Any help is greatly appreciated.
You need to make sure you are setting a higher timeout limit both in PHP and in Apache.
If you set a high max_execution_time in php.ini your script won't timeout, however, if you are not flushing the output butter of the script's results to the browser on a regular basis, the script might time out on the Apache end due to a network timeout.
In httpd.conf do:
Timeout 216000
In php.ini do:
max_execution_time = 0
(setting it to 0 makes it never time out, like with a CLI (command line) script).
Make sure you restart Apache after you are done! On most linux distro's you can do this by issuing the command (as root):
service httpd restart
Hope this helps!
There are numerous places that the maxtime can be set. If you are using FastCGI, especially though something such as Virtualmin, there are an additional set of settings for max_execution_time that are hidden to you unless you have access.
In short, you will need to figure out all the places, given your PHP stack setup, there can be an execution time limiter, up those values, restart the server, and then do
set_time_limit(0);
for good measure.
Without more information about your specific setup and given my experience in dealing with execution time hangups in PHP, that's the most I can tell you.
I am running a huge import to my database(about 200k records) and I'm having a serious issue with my import script timing out. I used my cell phone as a stop watch and found that it times out at exactly 45 seconds every pass(internal server error)... it only does about 200 records at a time, sometimes less. I scanned my phpinfo() and nothing is set to 45 seconds; so, I am clueless as to why it would be doing this.
My max_execution_time is set to 5 minutes and my max_input_time is set to 60 seconds. I also tried setting set_time_limit(0); ignore_user_abort(1); at the top of my page but it did not work.
It may also be helpful to note that my error file reads: "Premature end of script headers" as the execution error.
Any assistance is greatly appreciated.
I tried all the solutions on this page and, of course, running from the command line:
php -f filename.php
as Brent says is the sensible way round it.
But if you really want to run a script from your browser that keeps timing out after 45 seconds with a 500 internal server error (as I found when rebuilding my phpBB search index) then there's a good chance it's caused by mod_fcgid.
I have a Plesk VPS and I fixed it by editing the file
/etc/httpd/conf.d/fcgid.conf
Specifically, I changed
FcgidIOTimeout 45
to
FcgidIOTimeout 3600
3600 seconds = 1 hour. Should be long enough for most but adjust upwards if required. I saw one example quoting 7200 seconds in there.
Finally, restart Apache to make the new setting active.
apachectl graceful
HTH someone. It's been bugging me for 6 months now!
Cheers,
Rich
It's quite possible that you are hitting an enforced resource limit on your server, especially if the server isn't fully under your control.
Assuming it's some type of Linux server, you can see your resource limits with ulimit -a on the command line. ulimit -t will also show you just the limits on cpu time.
If your cpu is limited, you might have to process your import in batches.
First, you should be running the script from the command line if it's going to take a while. At the very least your browser would timeout after 2 minutes if it receives no content.
php -f filename.php
But if you need to run it from the browser, try add header("Content-type: text/html") before the import kicks.
If you are on a shared host, then it's possible there are restrictions on the system when any long running queries and/or scripts are automatically killed after a certain length of time. These restrictions are generally loosened for non-web running scripts. Thus, running it from the command line would help.
The 45 seconds could be a coincidence -- it could be how long it takes for you to reach the memory limit.. increasing the memory limit would be like:
ini_set('memory_limit', '256M');
It could also be the actual db connection that is timing out.. what db server are you using?
For me, mssql times out with an extremely unhelpful error, "Database context changed", after 60 seconds by default. To get around this, you do:
ini_set('mssql.timeout', 60 * 10); // 10 min
First of all
max_input_time and
set_time_limit(0)
will only work with VPS or dedicated servers . Instead of that you can follow some rules to your implementation like below
First read the whole CSV file .
Then grab only 10 entries (rows) or less and make a ajax calls to import in DB
Try to call ajax every time with 10 entries and after that echo out something on browser . In this method your script will never timeout .
Follow the same method untill the CSV rows are finished .
I have a bunch of client point of sale (POS) systems that periodically send new sales data to one centralized database, which stores the data into one big database for report generation.
The client POS is based on PHPPOS, and I have implemented a module that uses the standard XML-RPC library to send sales data to the service. The server system is built on CodeIgniter, and uses the XML-RPC and XML-RPCS libraries for the webservice component. Whenever I send a lot of sales data (as little as 50 rows from the sales table, and individual rows from sales_items pertaining to each item within the sale) I get the following error:
Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 54 bytes)
128M is the default value in php.ini, but I assume that is a huge number to break. In fact, I have even tried setting this value to 1024M, and all it does is take a longer time to error out.
As for steps I've taken, I've tried disabling all processing on the server-side, and have rigged it to return a canned response regardless of the input. However, I believe the problem lies in the actual sending of the data. I've even tried disabling the maximum script execution time for PHP, and it still errors out.
Changing the memory_limit by ini_set('memory_limit', '-1'); is not a proper solution. Please don't do that.
Your PHP code may have a memory leak somewhere and you are telling the server to just use all the memory that it wants. You wouldn't have fixed the problem at all. If you monitor your server, you will see that it is now probably using up most of the RAM and even swapping to disk.
You should probably try to track down the offending code in your code and fix it.
ini_set('memory_limit', '-1'); overrides the default PHP memory limit.
The correct way is to edit your php.ini file.
Edit memory_limit to your desire value.
As from your question, 128M (which is the default limit) has been exceeded, so there is something seriously wrong with your code as it should not take that much.
If you know why it takes that much and you want to allow it set memory_limit = 512M or higher and you should be good.
The memory allocation for PHP can be adjusted permanently, or temporarily.
Permanently
You can permanently change the PHP memory allocation two ways.
If you have access to your php.ini file, you can edit the value for memory_limit to your desire value.
If you do not have access to your php.ini file (and your webhost allows it), you can override the memory allocation through your .htaccess file. Add php_value memory_limit 128M (or whatever your desired allocation is).
Temporary
You can adjust the memory allocation on the fly from within a PHP file. You simply have the code ini_set('memory_limit', '128M'); (or whatever your desired allocation is). You can remove the memory limit (although machine or instance limits may still apply) by setting the value to "-1".
It's very easy to get memory leaks in a PHP script - especially if you use abstraction, such as an ORM. Try using Xdebug to profile your script and find out where all that memory went.
When adding 22.5 million records into an array with array_push I kept getting "memory exhausted" fatal errors at around 20M records using 4G as the memory limit in file php.ini. To fix this, I added the statement
$old = ini_set('memory_limit', '8192M');
at the top of the file. Now everything is working fine. I do not know if PHP has a memory leak. That is not my job, nor do I care. I just have to get my job done, and this worked.
The program is very simple:
$fh = fopen($myfile);
while (!feof($fh)) {
array_push($file, stripslashes(fgets($fh)));
}
fclose($fh);
The fatal error points to line 3 until I boosted the memory limit, which
eliminated the error.
I kept getting this error, even with memory_limit set in php.ini, and the value reading out correctly with phpinfo().
By changing it from this:
memory_limit=4G
To this:
memory_limit=4096M
This rectified the problem in PHP 7.
You can properly fix this by changing memory_limit on fastcgi/fpm:
$vim /etc/php5/fpm/php.ini
Change memory, like from 128 to 512, see below
; Maximum amount of memory a script may consume (128 MB)
; http://php.net/memory-limit
memory_limit = 128M
to
; Maximum amount of memory a script may consume (128 MB)
; http://php.net/memory-limit
memory_limit = 512M
When you see the above error - especially if the (tried to allocate __ bytes) is a low value, that could be an indicator of an infinite loop, like a function that calls itself with no way out:
function exhaustYourBytes()
{
return exhaustYourBytes();
}
Your site's root directory:
ini_set('memory_limit', '1024M');
After enabling these two lines, it started working:
; Determines the size of the realpath cache to be used by PHP. This value should
; be increased on systems where PHP opens many files to reflect the quantity of
; the file operations performed.
; http://php.net/realpath-cache-size
realpath_cache_size = 16k
; Duration of time, in seconds for which to cache realpath information for a given
; file or directory. For systems with rarely changing files, consider increasing this
; value.
; http://php.net/realpath-cache-ttl
realpath_cache_ttl = 120
Rather than changing the memory_limit value in your php.ini file, if there's a part of your code that could use a lot of memory, you could remove the memory_limit before that section runs, and then replace it after.
$limit = ini_get('memory_limit');
ini_set('memory_limit', -1);
// ... do heavy stuff
ini_set('memory_limit', $limit);
In Drupal 7, you can modify the memory limit in the settings.php file located in your sites/default folder. Around line 260, you'll see this:
ini_set('memory_limit', '128M');
Even if your php.ini settings are high enough, you won't be able to consume more than 128 MB if this isn't set in your Drupal settings.php file.
Change the memory limit in the php.ini file and restart Apache. After the restart, run the phpinfo(); function from any PHP file for a memory_limit change confirmation.
memory_limit = -1
Memory limit -1 means there is no memory limit set. It's now at the maximum.
Just add a ini_set('memory_limit', '-1'); line at the top of your web page.
And you can set your memory as per your need in the place of -1, to 16M, etc..
For Drupal users, this Chris Lane's answer of:
ini_set('memory_limit', '-1');
works but we need to put it just after the opening
<?php
tag in the index.php file in your site's root directory.
PHP 5.3+ allows you to change the memory limit by placing a .user.ini file in the public_html folder.
Simply create the above file and type the following line in it:
memory_limit = 64M
Some cPanel hosts only accept this method.
Crash page?
(It happens when MySQL has to query large rows. By default, memory_limit is set to small, which was safer for the hardware.)
You can check your system existing memory status, before increasing php.ini:
# free -m
total used free shared buffers cached
Mem: 64457 63791 666 0 1118 18273
-/+ buffers/cache: 44398 20058
Swap: 1021 0 1021
Here I have increased it as in the following and then do service httpd restart to fix the crash page issue.
# grep memory_limit /etc/php.ini
memory_limit = 512M
For those who are scratching their heads to find out why on earth this little function should cause a memory leak, sometimes by a little mistake, a function starts recursively call itself for ever.
For example, a proxy class that has the same name for a function of the object that is going to proxy it.
class Proxy {
private $actualObject;
public function doSomething() {
return $this->actualObjec->doSomething();
}
}
Sometimes you may forget to bring that little actualObjec member and because the proxy actually has that doSomething method, PHP wouldn't give you any error and for a large class, it could be hidden from the eyes for a couple of minutes to find out why it is leaking the memory.
I had the error below while running on a dataset smaller than had worked previously.
Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 4096 bytes) in C:\workspace\image_management.php on line 173
As the search for the fault brought me here, I thought I'd mention that it's not always the technical solutions in previous answers, but something more simple. In my case it was Firefox. Before I ran the program it was already using 1,157 MB.
It turns out that I'd been watching a 50 minute video a bit at a time over a period of days and that messed things up. It's the sort of fix that experts correct without even thinking about it, but for the likes of me it's worth bearing in mind.
In my case on mac (Catalina - Xampp) there was no loaded file so I had to do this first.
sudo cp /etc/php.ini.default /etc/php.ini
sudo nano /etc/php.ini
Then change memory_limit = 512M
Then Restart Apache and check if file loaded
php -i | grep php.ini
Result was
Configuration File (php.ini) Path => /etc
Loaded Configuration File => /etc/php.ini
Finally Check
php -r "echo ini_get('memory_limit').PHP_EOL;"
Using yield might be a solution as well. See Generator syntax.
Instead of changing the PHP.ini file for a bigger memory storage, sometimes implementing a yield inside a loop might fix the issue. What yield does is instead of dumping all the data at once, it reads it one by one, saving a lot of memory usage.
The reason for this error is that your server configuration has a very low memory limit. Try adding this to wp-config.php (put it after <?php in this file):
define('WP_MEMORY_LIMIT', '96M');
Please note that this limit is OK for the theme and the plugins that come with the theme. If you want to enable other plugins you may need to increase the limit further.
define('WP_MEMORY_LIMIT', '256M');
Running the script like this (cron case for example): php5 /pathToScript/info.php produces the same error.
The correct way: php5 -cli /pathToScript/info.php
If you're running a WHM-powered VPS (virtual private server) you may find that you do not have permissions to edit PHP.INI directly; the system must do it. In the WHM host control panel, go to Service Configuration → PHP Configuration Editor and modify memory_limit:
I find it useful when including or requiring _dbconnection.php_ and _functions.php in files that are actually processed, rather than including in the header. Which is included in itself.
So if your header and footer is included, simply include all your functional files before the header is included.
Greetings is a very common problem because if you have very little memory allocated to php and your website is growing will require more resources.
I found myself in a site that had problems that gave error 500 to modify only some products, the problem was that they had used very heavy images in those specific products, solution:
1.- Increase "memory_limit" in php.ini
2.- Lower the weight of the images.
3.- Adapt again "memory_limit" to an acceptable value "512M" at least for me more than enough.
now it is important that you verify that the changes are being made because php apart from having several versions and several types of installations on the server, maybe you modify one and it does not work and this is because you are not modifying the correct php.ini file.
How do you verify that you are modifying the correct file?
In the prestashop dashboard go to advanced settings/information there you can see "Memory limit".
always remember that after making a change in the php.ini file it is advisable to restart apache or Nginx.
Ubuntu: sudo services apache2 restart
IMPORTANT NOTE: Never set the "memory_limit = -1" as many people mention here. The problem is that if you have a problem with a file or module you could be in a continuous loop consuming all the server's memory and processor. Let's take a simple example: a module has an error and makes a call to a function and until it is not positive it keeps calling, this will create an infinite loop and it will never stop doing it because php has no limit.
I hope it helps colleagues who have this problem.
The most common cause of this error message for me is omitting the "++" operator from a PHP "for" statement. This causes the loop to continue forever, no matter how much memory you allow to be used. It is a simple syntax error, yet is difficult for the compiler or runtime system to detect. It is easy for us to correct if we think to look for it!
But suppose you want a general procedure for stopping such a loop early and reporting the error? You can simply instrument each of your loops (or at least the innermost loops) as discussed below.
In some cases such as recursion inside exceptions, set_time_limit fails, and the browser keeps trying to load the PHP output, either with an infinite loop or with the fatal error message which is the topic of this question.
By reducing the allowed allocation size near the beginning of your code you might be able to prevent the fatal error, as discussed in the other answers.
Then you may be left with a program that terminates, but is still difficult to debug.
Whether or not your program terminates, instrument your code by inserting BreakLoop() calls inside your program to gain control and find out what loop or recursion in your program is causing the problem.
The definition of BreakLoop is as follows:
function BreakLoop($MaxRepetitions=500,$LoopSite="unspecified")
{
static $Sites=[];
if (!#$Sites[$LoopSite] || !$MaxRepetitions)
$Sites[$LoopSite]=['n'=>0, 'if'=>0];
if (!$MaxRepetitions)
return;
if (++$Sites[$LoopSite]['n'] >= $MaxRepetitions)
{
$S=debug_backtrace(); // array_reverse
$info=$S[0];
$File=$info['file'];
$Line=$info['line'];
exit("*** Loop for site $LoopSite was interrupted after $MaxRepetitions repetitions. In file $File at line $Line.");
}
} // BreakLoop
The $LoopSite argument can be the name of a function in your code. It isn't really necessary, since the error message you will get will point you to the line containing the BreakLoop() call.
In my case it was a brief issue with the way a function was written. A memory leak can be caused by assigning a new value to a function's input variable, e.g.:
/**
* Memory leak function that illustrates unintentional bad code
* #param $variable - input function that will be assigned a new value
* #return null
**/
function doSomehting($variable){
$variable = 'set value';
// Or
$variable .= 'set value';
}
Increasing the memory_limit fixed the problem. However, I had problems finding the memory limit. I am working on my project directly from live server, so if you're doing the same, on cPanel you can find the memory_limit if you go to Software - MultiPHP INI Editor and select the location. I increased mine from 256M to 512M. You can also find instructions here.