Bug #54864 [Com]: Memory leak associated with mysql connector

Edit report at https://bugs.php.net/bug.php?id=54864&edit=1 ID: 54864 Comment by: jas at rephunter dot net Reported by: jas at rephunter dot net Summary: Memory leak associated with mysql connector Status: Re-Opened Type: Bug Package: MySQLi related Operating System: FreeBSD PHP Version: 5.3.6 Block user comment: N Private report: N New Comment: The problem seems to be worse than previously. The following results are on PHP 5.5.27. On every loop while reading a table, memory is consumed, regardless of using gc_enable, unset, or mysqli_free_memory. I started by dusting off the script that I originally provided in this bug ticket on 2011-07-05. However that complexity is not needed, and a very simple query of "SELECT * from user" gives the same result. Here is the main loop of the simplified version, where the user table has about 70,000 rows: $rs = mysqli_query($link, 'SELECT * FROM user'); if ($rs) { // main loop $cnt = 0; echo 'after SQL mem=', memory_get_usage(true), LF; while($row = mysqli_fetch_row($rs)) { if (++$cnt % 3000 == 0) { echo ' id=', $row[$userid_ix], ' mem=', memory_get_usage(true), LF; gc_collect_cycles(); flush(); ob_flush(); // documentation is inconclusive whether this is also needed } unset($row); // $row = null; } } Here is the output of the above script (please note that the echo statements are issued once for every 3000 rows): Test Autoemail Memory Leak Using mysqli_connect start run mem=524288 Query SELECT * FROM user after SQL mem=24117248 id=3043 mem=29884416 id=6066 mem=35913728 id=9041 mem=41680896 id=12031 mem=47710208 id=15015 mem=53477376 id=17986 mem=59506688 id=20984 mem=65273856 id=24004 mem=71303168 id=27065 mem=77070336 id=30076 mem=83099648 id=33115 mem=88866816 id=36201 mem=94896128 id=39095 mem=100663296 id=42106 mem=106692608 id=45112 mem=112459776 id=48104 mem=118489088 id=51085 mem=124518400 id=54082 mem=130285568 PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 32 bytes) in /Users/jas/Websites/RepHunter/current/test-autoemail-memory.php on line 44 The various attempts to reclaim memory (gc_enable(), unset(), gc_reclaim_cycles, and setting the $row to null, all have no effect. At this point, the workaround is to simply set memory large enough, and hope the application completes before exhausting memory. At present I am using ini_set('memory_limit', '384M'); The problem (on line 44) is while($row = mysqli_fetch_row($rs)). Has anybody come up with an alternative to that construct that does not continue to consume memory? Previous Comments: ------------------------------------------------------------------------ [2015-09-03 17:18:42] jas at rephunter dot net I am the OP for this ticket. Our system, now at PHP 5.6.9, is once again experiencing a memory leak, and in fact it is in the same script as in the original post. I am planning to do some testing to see if unsetting things helps. But per the post from yesterday from supraguy, that does not work. ------------------------------------------------------------------------ [2015-09-02 20:53:41] supraguy at yandex dot com I run into the same problem as well. I use mysqli_query() and on each execution it increases by 50 or so bytes. I unset the crap out of everything and do mysqli_free_result() but still the number keeps rising. ------------------------------------------------------------------------ [2015-05-17 19:26:24] pr0ger at free dot fr Note : same leakage using mysql_fetch_row() or mysql_fetch_array() ------------------------------------------------------------------------ [2015-05-17 19:22:00] pr0ger at free dot fr Reproduced the memory leakage in php 5.5.0 + win7 had to fetch through 10M lines of TINYTEXT string (randoms from 4 to 250 utf8 chars) $pt = mysql_query("SELECT tinytext_data, int_primkey FROM buffer"); while ($line = mysql_fetch_array($pt)) { //doesnt need to do anything echo "\r\n". memory_get_usage(); } at each step, it increase the mem usage by 64 bytes, never freeing them. ------------------------------------------------------------------------ [2013-02-18 00:34:51] php-bugs at lists dot php dot net No feedback was provided. The bug is being suspended because we assume that you are no longer experiencing the problem. If this is not the case and you are able to provide the information that was requested earlier, please do so and change the status of the bug back to "Open". Thank you. ------------------------------------------------------------------------ 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 https://bugs.php.net/bug.php?id=54864 -- Edit this bug report at https://bugs.php.net/bug.php?id=54864&edit=1