PHP 4.0 Bug #10204 Updated: fgets causes memory leaks

ID: 10204 User Update by: pallmall@hushmail.com Status: Open Bug Type: Sockets related Description: fgets causes memory leaks > Um, yes, the memory usage increases because you are appending an infinite number of copies of the google page to your $page variable. No, that's what the unset is for. Anyways, here's memory statistics. On loading script one: 3740kb RAM used after two iterations (RAM should not increase above this level). After 5 minutes: 4130kb. Cf script two: 3752kb RAM used initially, and 3752kb after 5 minutes. These statistics aren't especially dramatic, but in other conditions it can be catastrophic. Regarding fclose, no this doesn't help. There is a problem with fgets but not fread. Previous Comments: --------------------------------------------------------------------------- [2001-04-09 06:58:37] pallmall@hushmail.com > Um, yes, the memory usage increases because you are appending an infinite number of copies of the google page to your $page variable. No, that's what the unset is for. Anyways, here's memory statistics. On loading script one: 3740kb RAM used after two iterations (RAM should not increase above this level). After 5 minutes: 4130kb. Cf script two: 3752kb RAM used initially, and 3752kb after 5 minutes. These statistics aren't especially dramatic, but in other conditions it can be catastrophic. Regarding fclose, no this doesn't help. There is a problem with fgets but not fread. --------------------------------------------------------------------------- [2001-04-06 09:19:49] wez@php.net Um, yes, the memory usage increases because you are appending an infinite number of copies of the google page to your $page variable. I can't see any leak in PHP - no leaks are reported by the memory manager. Can you give me more information about how the memory usage increases, and what you would expect it to be? Could you try explicitly fclose()ing your $fps too - you might find it useful in reducing memory cost. --Wez. --------------------------------------------------------------------------- [2001-04-06 08:54:33] wez@php.net I noticed this last night in the socket code: it uses a simple read-buffering scheme where the read buffer will only grow, so we are effectively storing the everything we have read in memory. However, I would expect the behaviour to be the same with fread. I take it the memory usage returns to normal once the page has completed? --Wez. --------------------------------------------------------------------------- [2001-04-06 07:54:22] pallmall@hushmail.com Try this script (tested on windows, linux and open BSD(: <?php set_time_limit(0); while (1) { unset($page); print "iteration ". ++$c; $fp = fsockopen("google.com", 80); fwrite($fp, "GET / HTTP/1.0rnrn"); while (!feof($fp)) { $page .= fgets($fp, 1000); } } ?> Run it with top or whatever running and watch the memory usage go up and up (not especially quickly because the page is small, but in certain situations I've had memory chewage of 1mb/minute). Now cf. <?php set_time_limit(0); while (1) { unset($page); print "iteration ". ++$c; $fp = fsockopen("google.com", 80); fwrite($fp, "GET / HTTP/1.0rnrn"); while (!feof($fp)) { $page .= fread($fp, 1000); } } ?> Memory usage remains constant here. [This meant I had to rewrite the readLine method in Net_Socket to use fread instead of fgets.] --------------------------------------------------------------------------- Full Bug description available at: http://bugs.php.net/?id=10204