php daemon possible memory leak

i've written a daemon in php and want to make sure it doesn't leak memory, as it'll be running 24/7.

even in its simplest form memory_get_peak_usage for a daemon will report that the script consumes more memory for each cycle. memory_get_usage on the other hand will not grow.

the question is: should i worry? i've stripped down the daemon to the bare 开发者_如何学运维basics but this is still happening. any thoughts?

#!/usr/bin/php -q

<?php
require_once "System/Daemon.php";
System_Daemon::setOption("appName", "smsd");
System_Daemon::start();
while(!System_Daemon::isDying()){
 System_Daemon::info("debug: memory_get_peak_usage: ".memory_get_peak_usage());
 System_Daemon::info("debug: memory_get_usage: ".memory_get_usage());
 System_Daemon::iterate(2);
}

FINAL NOTE + CONCLUSION: i ended up writing my own daemon wrapper, not using pear's system_daemon. regardless of how i tweaked this library i could not stop it from leaking memory. hope this helps someone else.

FINAL NOTE + CONCLUSION 2: my script has been in production for over a week and is still not leaking 1 bytes of memory. so - writing a daemon in php actually seems to be ok, as long as you're very careful about its memory consumtion.

I got the same problem. Maybe the best idea is to report new bug at PEAR

BTW, code like that doesn't show that memleak:

#!/usr/bin/php -q

<?php
require_once "System/Daemon.php";
System_Daemon::setOption("appName", "smsd");
System_Daemon::start();
while(!System_Daemon::isDying()) {
 print ("debug: memory_get_peak_usage: ".memory_get_peak_usage()."\n");
 print ("debug: memory_get_usage: ".memory_get_usage()."\n\n");
 System_Daemon::iterate(2);

}

Look's like System_Daemon::info() is a problem.

It turns out file_get_contents was leaking memory. Whenever I disabled that one line, peak memory usage was stable. When I commented it back in, peak memory usage would increase by 32 bytes every iteration.

Replaced the file_get_contents call (used to retrieve the number inside the pid-file in /var/run) with fread, and solved this problem.

This patch will be part of the next System_Daemon release.

Thanks whoever (can't find matching nick) also reported this bug (#18036) otherwise I'd probably never known.

Thanks again!

You can try using the new garbage collector in PHP 5.3 to prevent issues with circular references.

• gc_enable()
• gc_collect_cycles()

You should not use PHP to write a daemon. Why? Because PHP is not a language that is sufficiently mature to run for hours, days, weeks or months. PHP is written in C, all of the magic that it provides has to be handled. Garbage collection, depending on your version, might or might not work, depending on what extensions you have compiled and used. Yes, if they ship with official releases, they should 'play nice', but do you check to see what release you are using? Are you sure all loaded extensions realize that they might run for more than 10 - 30 seconds? Given that most execution times never spot leaks, are you sure it even works?

I am quite close to going off on a 'don't use regex to parse HTML rant' regarding this, as I see the question creeping up more and more. Twice today that I'm aware of.

Would you use a crowbar as a toothpick? Neither Zend, nor Roadsend, Nor PHC is sufficiently mature to handle running for any period of time that could be considered protracted, given the expected life of a PHP process when rendering a web page. Yes, even with the GC facilities provided by C++ based PHP compiler, it is unwise to write a daemon in PHP.

I hate answers that say you can't do that, with that, but in this case, it's true, at least for now.