The document discusses moving away from traditional backend architectures towards more real-time and distributed systems. It advocates for storing data in a distributed database and processing it asynchronously in batches to improve user experience. Concrete examples are given of using protocols like ProtoBufs over REST, writing data from mobile clients to partitions, and performing analytics on batches of data later.

1. from
hand
to
mouth

2. Pavlo Baron
pavlo.baron@codecentric.de
@pavlobaron

3. Forget backend

4. Or at least what
you call a backend

5. Your application server
will just slow down
your machines to
keep step with them

6. Or you will slow down
your incoming traffic
to give your application
server a chance to
breathe

7. User experience:
order food
at McDonalds, get
queued and receive
the ordered food
through mail 3
days later

8. User experience with some
psychology: order food at
McDonalds, get queued,
leave the restaurant
with color pictures of
your food and wait 3
days for its delivery

9. Every single data
abstraction layer only
helps ruin the
atmosphere through
heating

10. Hey, man,
you carry around a damn
USS Enterprise in your
pocket
And you can run a
damn Babylon 5 in
a cluster

11. And in the end, it's
always store/update/
delete/read/search/
process.
Isn't it?

12. So why drive a clown car
when you can have
a Ferrari
full of these?

13. Why not just live
from hand to mouth?

14. You haz this:
Your user. Totally drunk in
a football stadium. Just
wants to inform the world
that Ronaldo has scored a
goal. Shaking hand, lots of
typos and confusion.

15. You want this:
Let him protocol the fact at
any cost.
Look at it later, together
with further facts to make
a picture of the sports fact.

16. Concrete:
Mobile clients write from
everywhere, buffer,
read occasionally,
post-processing completely
behind the scenes, like
statistics etc.

17. Even more concrete:
Immediate, reliable, massive
writes. Analytics and
processing in a batch
afterwards. No need to
be exact to the second
and 100% data complete

18. More concrete:

19. Very concrete:
ProtoBufs, REST
Round Robin
local
REST, local Erlang client
Buffer
Web Apps,
R,
tools etc.

20. Infrastructure can be solved.
More challenging is how
to get structured records out
of a bunch of facts written by
shaking hands.
That's different story tho.

21. HTF does it work?

22. Da core

23. Da ring
X bit integer space
0 <= N <= 2 ^ X
or: 2 x Pi
0 <= A <= 2 x Pi
x(N) = cos(A)
y(N) = sin(A)

24. Da cluster
12 partitions (constant)
3 nodes, 4 vnodes each
add node
4 nodes, 3 vnodes each
Alternatives:
3 nodes, 2 x 5 + 1 x 2 vnodes
container based

25. Da quorum
V: vnodes holding a key
W: write quorum
R: read quorum
DW, PW, PR
W > 0.5 * V
R+W>V

26. Insert key
Key = “foo”
# = N, W = 2 (sloppy quorum)
replicate
N
ok

27. Add node
co
py
leave
leave
co
py
y
leave
p
co

28. Lookup key
(sloppy
N quorum)
Value = “bar”
Key = “foo”
# = N, R = 2

29. Remove
node
copy
leave

30. write RM2 Da Gossip
RM1
Clock table
Value
Update log stable clock
Replica clock updates
Value
Executed operation table

31. Da vector clocks
Node 1
1,0,0 2,2,0 3,2,0 4,3,3
Node 2
1,1,0 1,2,0 1,3,3 4,4,3
Node 3
1,0,1 1,2,2 1,2,3 4,3,4

32. Da MapReduce
query =
Node X "Alice"
map reduce hit
list
map map
N= N= N=
„Alice" "Alice" "Alice"
Node A Node B Node C

33. Da hinted handoff
N: node, G: group including N
node(N) is unavailable
replicate to G or
store data(N) locally
hint handoff for later
node(N) is alive
handoff data to node(N)

34. Key = “foo”, # = N -> Replica
handoff hint = true fails
Key = “foo”
N
replicate

35. Replica
handoff recovers

36. And that's by far not all:
You can search through
index with data locality.
You can tag objects and
query through 2i.
You can add hooks.

37. You don't even need to store
anything.
Just distribute your
calculation, search, batch

38. Have a look at tendita.com

39. So it's even comfy to load
your clown car
with these

40. Thank you

41. Most images originate from
istockphoto.com
except few ones taken
from Wikipedia or Flickr (CC)
and product pages/
publicly available presentations
or generated through public
online generators