XF 1.2 "MySQL Has Gone Away" On Registration


Well-known member
Odd problem here. We're getting the infamous "MySQL has gone away" problem when some (but not all) users try to register on our site, after they click Submit. The stack trace is as follows:

An exception occurred: Mysqli prepare error: MySQL server has gone away in /home/pcharms/public_html/library/Zend/Db/Statement/Mysqli.php on line 77
    Zend_Db_Statement_Mysqli->_prepare() in Zend/Db/Statement.php at line 115
    Zend_Db_Statement->__construct() in Zend/Db/Adapter/Mysqli.php at line 381
    Zend_Db_Adapter_Mysqli->prepare() in Zend/Db/Adapter/Abstract.php at line 478
    Zend_Db_Adapter_Abstract->query() in Zend/Db/Adapter/Abstract.php at line 808
    Zend_Db_Adapter_Abstract->fetchPairs() in XenForo/Phrase.php at line 332
    XenForo_Phrase::loadPhrases() in XenForo/Template/Abstract.php at line 186
    XenForo_Template_Abstract->render() in XenForo/Template/Public.php at line 110
    XenForo_Template_Public->render() in NodesAsTabs/NavTabs.php at line 126
    call_user_func_array() in XenForo/CodeEvent.php at line 90
    XenForo_CodeEvent::fire() in XenForo/Dependencies/Public.php at line 491
    XenForo_Dependencies_Public->_getNavigationContainerParams() in XenForo/Dependencies/Public.php at line 371
    XenForo_Dependencies_Public->getEffectiveContainerParams() in XenForo/FrontController.php at line 612
    XenForo_FrontController->renderView() in XenForo/FrontController.php at line 158
    XenForo_FrontController->run() in /home/pcharms/public_html/index.php at line 13
Originally thinking this was load, we tried restarting the server and getting the user to register immediately afterwards with the load at minimum, with no effect. We also disabled listeners (to forcibly disable the CPU-hungry application we use and to ensure no add-on issues were causing the problem.

We're on an Apache 2.4 box with MySQL 5.5, PHP 5.5, Memcached, and the Zend Opcache, if that helps any.