I will look in to this and get back to you as soon as I get some more information. I am not a DB expert so will take me some time to gather some resources.
But this is an area where I would like to improve my understanding. So I will challenge my self to write a blog post answering your questions in the mean time. I will also post my finding here.
And will ping @piwi for visibility to remind me to add request for more content on this topic.