#28131 [Bgs]: refcount limit is 64k

ID: 28131 Updated by: wez@php.net -Summary: Scripts can't consume more than 64MB on Windows XP/2000 Reported By: webmaster at macway dot com Status: Bogus Bug Type: Reproducible crash Operating System: Windows XP PHP Version: 4.3.6 New Comment: ah, this bug. It is to do with the COW reference created by the engine when you copy $chunk around. Since it is the same chunk, the engine saves copying the 1MB and adds a reference to the variable. The problem is that ZE1 has a limit of 64k references before it overflows and causes this problem. It has nothing to do with memory usage. It is a known bug in this database (although I couldn't find it just now; it *is* in here somewhere). This problem will not be fixed in PHP 4.x, but has already been addressed in PHP 5. Workaround: use $toto .= str_repeat('a', 1024) inside the main loop, as this returns unique strings on each iteration. Previous Comments: ------------------------------------------------------------------------ [2004-04-26 18:02:22] webmaster at macway dot com > wez Ok perharps its works with str_repeat, but it doesn't seem to work with array. Please check with my code. Maybe I badly worded it,; maybe it's just with arrays, check with my lateest code please ------------------------------------------------------------------------ [2004-04-26 17:53:33] webmaster at macway dot com As I just said, I retested it with PHP 4.3.6 ALONE (without any webserver) using the php.exe under windows XP. So it's clearly a problem with PHP 4.3.6 itself ------------------------------------------------------------------------ [2004-04-26 17:32:16] wez@php.net Sorry, but your problem does not imply a bug in PHP itself. For a list of more appropriate places to ask for help using PHP, please visit http://www.php.net/support.php as this bug system is not the appropriate forum for asking support questions. Thank you for your interest in PHP. My 512MB laptop running XP will allocate 800MB (probably as much as the page file size, if I pushed it). C:\php4>php -r "$x = str_repeat('*', 128 * 1024 * 1024); echo 'Done';" Done C:\php4>php -r "$x = str_repeat('*', 400 * 1024 * 1024); echo 'Done';" Done C:\php4>php -r "$x = str_repeat('*', 600 * 1024 * 1024); echo 'Done';" Done C:\php4>php -r "$x = str_repeat('*', 800 * 1024 * 1024); echo 'Done';" Done C:\php4>php -r "$x = str_repeat('*', 1280 * 1024 * 1024); echo 'Done';" FATAL: emalloc(): Unable to allocate 1342177281 bytes It works fine; no crashes. You must have something wrong with your configuration; check your memory_limit and error_reporting settings and talk to someone on a support channel to discover the reason that you have problems with this. ------------------------------------------------------------------------ [2004-04-26 16:58:08] webmaster at macway dot com Faster code exhibiting the problem : <?php for ($i = 1; $i <= 1024; $i++) // I'm just making a 1024 Byte string { $chunk .='a'; } for ($i = 1; $i <= 66000; $i++) // if you use 65000 it works { $tablo[]=$chunk; } echo "c'est fini"; ?> ------------------------------------------------------------------------ [2004-04-26 16:55:59] webmaster at macway dot com THE PROBLEM IS VERY SERIOUS : it crashes the php engine on Windows XP. It is reproductible. I've redonne some tests and it appears that the web server is nit the issue (launching the php.exe without any webserver exhibits the problem). I've you have 4 different variables, then the max size of each will be 64/4 = 16MB of ram max. That means the total ram consumed by the script has to be lower than 64MB ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/28131 -- Edit this bug report at http://bugs.php.net/?id=28131&edit=1