From Hand To Mouth (@pavlobaron)

fromhandtomouth

Pavlo Baronpavlo.baron@codecentric.de @pavlobaron

Forget backend

Or at least whatyou call a backend

Your application serverwill just slow downyour machines tokeep step with them

Or you will slow downyour incoming trafficto give your applicationserver a chance tobreathe

User experience:order foodat McDonalds, getqueued and receivethe ordered foodthrough mail 3days later

User experience with somepsychology: order food atMcDonalds, get queued,leave the restaurantwith color pictures ofyour food and wait 3days for its delivery

Every single dataabstraction layer onlyhelps ruin theatmosphere throughheating

Hey, man,you carry around a damnUSS Enterprise in yourpocket And you can run a damn Babylon 5 in a cluster

And in the end, itsalways store/update/delete/read/search/process.Isnt it?

So why drive a clown carwhen you can havea Ferrarifull of these?

Why not just livefrom hand to mouth?

You haz this:Your user. Totally drunk ina football stadium. Justwants to inform the worldthat Ronaldo has scored agoal. Shaking hand, lots oftypos and confusion.

You want this:Let him protocol the fact atany cost.Look at it later, togetherwith further facts to makea picture of the sports fact.

Concrete:Mobile clients write fromeverywhere, buffer,read occasionally,post-processing completelybehind the scenes, likestatistics etc.

Even more concrete:Immediate, reliable, massivewrites. Analytics andprocessing in a batchafterwards. No need tobe exact to the secondand 100% data complete

More concrete:

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

Infrastructure can be solved.More challenging is howto get structured records outof a bunch of facts written byshaking hands.Thats different story tho.

HTF does it work?

Da core

Da ringX bit integer space 0 <= N <= 2 ^ Xor: 2 x Pi 0 <= A <= 2 x Pi x(N) = cos(A) y(N) = sin(A)

Da cluster12 partitions (constant) 3 nodes, 4 vnodes eachadd node 4 nodes, 3 vnodes eachAlternatives: 3 nodes, 2 x 5 + 1 x 2 vnodes container based

Da quorumV: vnodes holding a keyW: write quorumR: read quorumDW, PW, PR W > 0.5 * V R+W>V

Insert keyKey = “foo”# = N, W = 2 (sloppy quorum) replicate N ok

Add node co py leaveleave co py y leave pco

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

Remove nodecopy leave

write RM2 Da Gossip RM1 Clock table Value Update log stable clockReplica clock updates Value Executed operation table

Da vector clocksNode 1 1,0,0 2,2,0 3,2,0 4,3,3Node 2 1,1,0 1,2,0 1,3,3 4,4,3Node 3 1,0,1 1,2,2 1,2,3 4,3,4

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

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

Key = “foo”, # = N -> Replicahandoff hint = true failsKey = “foo” N replicate

Replicahandoff recovers

And thats by far not all:You can search throughindex with data locality.You can tag objects andquery through 2i.You can add hooks.

You dont even need to storeanything.Just distribute yourcalculation, search, batch

Have a look at tendita.com

So its even comfy to loadyour clown carwith these

Thank you

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

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From Hand To Mouth (@pavlobaron)

by Pavlo Baron

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