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: Please note that in my above post with the simplified code, the flush() and ob_flush() are not directly related to the issue afaik, but have to do with attempts to display output in a browser. Previous Comments: ------------------------------------------------------------------------ [2015-09-10 13:51:52] jas at rephunter dot net 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? ------------------------------------------------------------------------ [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. ------------------------------------------------------------------------ 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