Bug #71468 [NEW]: increased memory usage with mysqli in php 7

From: ryan dot brothers at gmail dot com Operating system: Linux PHP version: 7.0.2 Package: MySQLi related Bug Type: Bug Bug description:increased memory usage with mysqli in php 7 Description: ------------ I am seeing an issue in PHP 7 where large database queries are taking up more memory compared to PHP 5.6. In the below example, PHP 7 uses 8.3MB while PHP 5.6 only uses 1.8MB. I have placed SQL to create a test table of 100,000 rows at https://drive.google.com/uc?export=download&id=0B37DKbJklxg_Y3NadnRjc2tVbE0. Is this expected behavior or an issue with PHP 7 memory usage? Thanks for your help. Test script: --------------- <?php $mysqli = new mysqli('localhost', 'test', 'test', 'test'); $mysqli->real_query("SELECT * FROM a"); $result = $mysqli->store_result(); echo memory_get_usage()."\n"; exit; Expected result: ---------------- PHP 5.6.17: 1832472 PHP 7.0.2: 1832472 (or close to it) Actual result: -------------- PHP 5.6.17: 1832472 PHP 7.0.2: 8356704 -- Edit bug report at https://bugs.php.net/bug.php?id=71468&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=71468&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=71468&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=71468&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=71468&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=71468&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=71468&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=71468&r=needscript Try newer version: https://bugs.php.net/fix.php?id=71468&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=71468&r=support Expected behavior: https://bugs.php.net/fix.php?id=71468&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=71468&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=71468&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=71468&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=71468&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=71468&r=dst IIS Stability: https://bugs.php.net/fix.php?id=71468&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=71468&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=71468&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=71468&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=71468&r=mysqlcfg