This simple contrib fixes the error:

PHP Fatal error: Uncaught exception 'mysqli_sql_exception' with message 'No index used in query/prepared statement delete from whos_online where time_last_click < '1278246100'' in

/var/www/vhosts/YOURDOMAIN/YOURDIRECTORY/YOUR_SUBDIR/includes/classes/database/mysqli.php:108

randomly shown in error_log

Although the error comes from mySQL database, it should be seen as a warning and not as an error, but OS3 debug reports it as a fatal error and sometimes it will cause a system crash. Often a 'RUNTIME SERVER ERROR 500' occurs on some working installations. This contrib simply TURNS OFF the mysqli error reporting system to avoid script blocking errors.

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