I'm currently facing a problem with my Magento 1.6 configured for multi-sites.
If a logged customer has something in his shopping cart, and, in the same time, I save a product in the admin, the customer will get blank page after 30 seconds and in my apache log, I get an "Allowed memory size" error.
If I make the same thing but the shopping cart of my customer is empty, there is no problem.
I can't find any error logged in exception.log or system.log, not even in apache log.
The only way to unlock the customer is to delete manually his session file on the server in root/var/session/.
I've already tried to push back my memory_limit parameter to 1024M, but still fails.
What can I do here ? I'm kinda lost for 1 day.