Re:Why I Migrated Away From MongoDB
by nerd_in_rage on Monday September 17, 2012 @08:25PM
(#4535615)
What? It's the absolute truth. If someone's wall post or tweet goes missing, it's totally inconsequential.
"Social graph" - LOL.
You think FB doesn't consider durability and consistency essential? With almost one billion users?!
Wow.
Whether it is consequential or not is completely beside the point. As is whether you understand the "social graph".
Re:Why I Migrated Away From MongoDB
by nerd_in_rage on Monday September 17, 2012 @11:27PM
(#4536146)
Eventual consistency, yes. What I'm saying is if a few pics disappear for a half hour while things resolve themselves, nobody is going to care... or likely notice.
It's not a bank.
By the way, I believe social networking is mostly bullshit, which is my "LOL" at the "social graph".
Eventual consistency however provides no guarantee of consistency unless it is backed by absolute local consistency on every node. Don't you run into CAP theorem problems otherwise?
Sure. But if a person or a photo data object goes missing ?
Facebook has different data stores for each of their features so I imagine the loss of a person would be pretty nasty as would a photo data object that multiple people have tagged or commented on.
My point is that when you are the size of Facebook, Twitter etc a loss of data in 0.001% of cases equates to a LOT of data and relationships.
Facebook and Instagram itself I imagine would care VERY much if data went missing as it would mean not just (a) user data going missing but (b) potentially huge inconsistencies in the social graph.
Unless you have some evidence that those companies do not care about data durability ?