Bug #77599 [NEW]: Unbuffered queries; native prepared statements memory leak

From: dylan at php dot waywardrambler dot com Operating system: MacOS 10.14.3 PHP version: 7.3.2 Package: PDO MySQL Bug Type: Bug Bug description:Unbuffered queries; native prepared statements memory leak Description: ------------ Memory leak when running unbuffered queries in PDO with ATTR_EMULATE_PREPARES set to false. Test script: --------------- <?php ini_set('memory_limit', '16M'); $pdo = new PDO('mysql:host=*;dbname=*', '*', '*'); $pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false); $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $pdo->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false); $result = $pdo->query("SELECT * FROM large_table"); foreach ($result as $i => $row) if ($i % 10000 === 0) printf("%10s %10s\n", $i, memory_get_usage()); Expected result: ---------------- consistent memory usage, eg: 0 2097152 10000 2097152 20000 2097152 30000 2097152 40000 2097152 Actual result: -------------- 0 2097152 10000 4194304 20000 8388608 30000 12582912 40000 14680064 Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 16384 bytes) in /php on line 10 -- Edit bug report at https://bugs.php.net/bug.php?id=77599&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=77599&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=77599&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=77599&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=77599&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=77599&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=77599&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=77599&r=needscript Try newer version: https://bugs.php.net/fix.php?id=77599&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=77599&r=support Expected behavior: https://bugs.php.net/fix.php?id=77599&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=77599&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=77599&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=77599&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=77599&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=77599&r=dst IIS Stability: https://bugs.php.net/fix.php?id=77599&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=77599&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=77599&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=77599&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=77599&r=mysqlcfg