Major database issues, server chrash

I’ve been trying to figure out for weeks now what caused my server to constantly crash. Unfortunately I traced it back to the woocommerce plugin. There seems to be some problem in the querys your using. These 3 errors kept poping up in my debug.log

PHP Notice:  Trying to get property of non-object in /wp-includes/class-wp-query.php on line 3736
PHP Notice:  Trying to get property of non-object in /wp-includes/class-wp-query.php on line 3738
PHP Notice:  Trying to get property of non-object in /wp-includes/class-wp-query.php on line 3740

It destroys several database tables and totally consumes the cpu and memory of the server. I’ve been finding more and more people with the same errors wondering what causes it, so you might want to take a look at it.