7. for {
x <- post.stream
user <- getUser(x)
message <- getData(x)
friend <- getFriends(user)
} {
yield notifyFriend(friend,user,message.id)
}
1 billion posts a day!
Example: Notify all my friends
22. Nature went that way too.
Ain’t that funny?
“Evolving to multi cellular
organisms”
More resiliant
cells die: organism lives on
Complex tasks:
cannot be handled by a single cell
30. CAP theorem: 12 years later
The CAP theorem is largely misunderstood.
31. High Availability
A system can be up, but not available
(think of a network outage: your system is in P mode)
How to improve it .
Replication / Redundancy:
3, 5 replicas are common in highly available systems
Dynamic Commission - Decommission:
re-balance the cluster for dead/new nodes