Bug #77554 [NEW]: memory leak while fetching

From: 13dagger at gmail dot com Operating system: archlinux PHP version: 7.3.1 Package: PDO MySQL Bug Type: Bug Bug description:memory leak while fetching Description: ------------ Problem happens if I request big table or table with lots of data in rows. Memory usage increasing drastically while fetching one row at a time. If I query only one field, ex id, memory usage grows slower. The code in example gives "PHP Fatal error: Allowed memory size" after fetching ~175 rows. Test example generates table, fill it and tries to fetch data row by row. Tested the code in php 7.2 and it worked as expected. Test script: --------------- <?php $db_name = ''; $db_user = ''; $db_pass = ''; ini_set('memory_limit', '10M'); $cn = 0; $pdo = new \PDO('mysql:host=localhost;dbname=' . $db_name, $db_user, $db_pass); $pdo->setAttribute(\PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false); $pdo->exec('DROP TABLE IF EXISTS test_mem_leak'); $pdo->exec('CREATE TABLE IF NOT EXISTS test_mem_leak (id INT AUTO_INCREMENT, txt TEXT, PRIMARY KEY(id))'); $fill = str_repeat('test-', 10000); for ($i = 0; $i < 500; ++$i) { $pdo->exec("INSERT INTO test_mem_leak SET txt = '$fill'"); } $q = $pdo->query('select * from test_mem_leak'); while ($d = $q->fetch()) { echo $cn . ' ' . round(memory_get_usage() / (1024 * 1024), 3) . "MB \n"; ++$cn; } echo "ok: $cn\n"; Actual result: -------------- PHP Fatal error: Allowed memory size of 10485760 bytes exhausted (tried to allocate 53248 bytes) in /home/me/code/tmp/1.php on line 16 -- Edit bug report at https://bugs.php.net/bug.php?id=77554&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=77554&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=77554&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=77554&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=77554&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=77554&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=77554&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=77554&r=needscript Try newer version: https://bugs.php.net/fix.php?id=77554&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=77554&r=support Expected behavior: https://bugs.php.net/fix.php?id=77554&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=77554&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=77554&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=77554&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=77554&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=77554&r=dst IIS Stability: https://bugs.php.net/fix.php?id=77554&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=77554&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=77554&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=77554&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=77554&r=mysqlcfg