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Distributed computation on dynamo-styledistributed storage: Riak pipe

An introduction to Riak

Jaseem Abid

September 19, 2012

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.. Riak

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.. What is Riak ?

Riak is an open source, distributed NoSQL database implementingthe principles from Amazon’s Dynamo paper.

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.. Dynamo Model

Riak is a highly available, proprietary key-value structured storagesystem or a distributed data store. It has properties of bothdatabases and distributed hash tables (DHTs). It is not directlyexposed as a web service, but is used to power parts of otherAmazon Web Services such as Amazon S3.

Implementations

Apache CassandraProject VoldemortRiakAmazon DynamoDB

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.. Dynamo Model

Riak is a highly available, proprietary key-value structured storagesystem or a distributed data store. It has properties of bothdatabases and distributed hash tables (DHTs). It is not directlyexposed as a web service, but is used to power parts of otherAmazon Web Services such as Amazon S3.

Implementations

Apache CassandraProject VoldemortRiakAmazon DynamoDB

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.. Dynamo Model

Riak is a highly available, proprietary key-value structured storagesystem or a distributed data store. It has properties of bothdatabases and distributed hash tables (DHTs). It is not directlyexposed as a web service, but is used to power parts of otherAmazon Web Services such as Amazon S3.

Implementations

Apache CassandraProject VoldemortRiakAmazon DynamoDB

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.. Dynamo Model

Riak is a highly available, proprietary key-value structured storagesystem or a distributed data store. It has properties of bothdatabases and distributed hash tables (DHTs). It is not directlyexposed as a web service, but is used to power parts of otherAmazon Web Services such as Amazon S3.

Implementations

Apache CassandraProject VoldemortRiakAmazon DynamoDB

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.. Dynamo Model

Riak is a highly available, proprietary key-value structured storagesystem or a distributed data store. It has properties of bothdatabases and distributed hash tables (DHTs). It is not directlyexposed as a web service, but is used to power parts of otherAmazon Web Services such as Amazon S3.

Implementations

Apache CassandraProject VoldemortRiakAmazon DynamoDB

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.. This talk

Front Matter

Dynamo (and NoSQL) are nothing newMuch of Dynamo was invented > 10 years agoDynamo chooses AP of CAPThis talk will focus on properties of Dynamo-inspired systems(Riak, Cassandra, Voldemort)

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.. CAP theorem

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.. CAP theorem

Consistent, writes are atomic and all subsequent requestsretrieve the new value

Available, the database will always return a value as long as asingle server is runningPartition Tolerant, the system will still function even if servercommunication is temporarily lost—that is, a networkpartitionYou can have only two at once.

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.. CAP theorem

Consistent, writes are atomic and all subsequent requestsretrieve the new valueAvailable, the database will always return a value as long as asingle server is running

Partition Tolerant, the system will still function even if servercommunication is temporarily lost—that is, a networkpartitionYou can have only two at once.

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.. CAP theorem

Consistent, writes are atomic and all subsequent requestsretrieve the new valueAvailable, the database will always return a value as long as asingle server is runningPartition Tolerant, the system will still function even if servercommunication is temporarily lost—that is, a networkpartition

You can have only two at once.

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.. CAP theorem

Consistent, writes are atomic and all subsequent requestsretrieve the new valueAvailable, the database will always return a value as long as asingle server is runningPartition Tolerant, the system will still function even if servercommunication is temporarily lost—that is, a networkpartitionYou can have only two at once.

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.. CAP theorem

Riak picks AP of CAP

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.. Eventual Consistency

Distributed databases must be partition tolerant, so thechoice between availability and consistency can be difficult.The real world is eventually consistent and works (mostly) fine*Eventual* doesn’t mean minutes, days, or even seconds innon-failure casesDNS, HTTP with Expires: headerHow you model the real world matters!

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.. Riak ArchitectureAmazon’s Dynamo architectureDistributed, Scalable, No single point of failureNo transactions; trade strong consistency for eventual consistency

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.. Simple Key Value data store - Store anything

Plain text, JSON, or XML to images or video clips—all accessiblethrough a simple HTTP interface

Riak KV

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.. Simple Key Value data store - Store anything

Plain text, JSON, or XML to images or video clips—all accessiblethrough a simple HTTP interfaceRiak KV

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.. Fault-Tolerant

Riak is also fault-tolerant. Servers can go up or down at anymoment with no single point of failure.

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.. Riak loves the web

Query Riak via URLs, headers, and verbs, and Riak returns assetsand standard HTTP response codes.

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.. Scalable

# start 4 nodes

$ dev/dev1/bin/riak start$ dev/dev2/bin/riak start$ dev/dev3/bin/riak start$ dev/dev4/bin/riak start

# scale out$ dev/dev2/bin/riak-admin join dev1@127.0.0.1

# scabe back in$ riak-admin leave

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.. Queriablity

REST APIEasy quick and dirtyMap ReduceProvide set of starting keys, filter via mapMap reduce is meant for calulations/ aggregations and not queries.Riak SearchFull text search in RiakOpinionatedRoll out your own indicesDifficult to get it rightMore code to maintainOften introduces SPOFs

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.. Riak REST API

Representational state transfer

Create Update Read Delete verbsRiak and cURL

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.. Riak REST API

Representational state transferCreate Update Read Delete verbs

Riak and cURL

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.. Riak REST API

Representational state transferCreate Update Read Delete verbsRiak and cURL

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.. REST API w/ curl

$ curl http://localhost:8091/pingOK

# Let’s issue a bad query.# -I tells cURL that we want only the header response.

$ curl -I http://localhost:8091/riak/no_bucket/no_keyHTTP/1.1 404 Object Not FoundServer: MochiWeb/1.1 WebMachine/1.7.3 \(participate in the frantic)

Date: Thu, 04 Aug 2011 01:25:49 GMTContent-Type: text/plainContent-Length: 10

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.. Lets PUT something in the DB

$ curl -v -X PUT http://localhost:8091/riak/favs/db \-H "Content-Type: text/html" \-d "<html>

<body><h1>

My new favorite DB is RIAK</h1>

</body></html>"

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.. Now get it back

curl -X GET http://localhost:8091/riak/favs/db

Or just hit the browser

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.. Or POST it

$ curl -I -X POST http://localhost:8091/riak/animals \-H "Content-Type: application/json" \-d '{

"nickname" : "Sergeant Stubby","breed" : "Terrier"

}'

HTTP/1.1 201 CreatedVary: Accept-EncodingServer: MochiWeb/1.1 WebMachine/1.7.3 \(participate in the frantic)Location: /riak/animals/6VZc2o7zKxq2B34kJrm1S0ma3PODate: Tue, 05 Apr 2011 07:45:33 GMTContent-Type: application/jsonContent-Length: 0

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.. Dump anything

curl -X PUT HTTP://127.0.0.1:8091/riak/images/1.jpg \-H "Content-type: image/jpeg" \--data-binary @image_name.jpg

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.. Or DELETE it

$ curl -I -X DELETE http://localhost:8091/riak/ \animals/6VZc2o7zKxq2B34kJrm1S0ma3PO

HTTP/1.1 204 No ContentVary: Accept-EncodingServer: MochiWeb/1.1 WebMachine/1.7.3 \(participate in the frantic)

Date: Mon, 11 Apr 2011 05:08:39 GMTContent-Type: application/x-www-form-urlencodedContent-Length: 0

DELETE won’t return any body, but the HTTP code will be 204 ifsuccessful. Otherwise, as you’d expect, it returns a 404.

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.. Map Reduce

Google :)*large* data setsFunctional ProgrammingApache HadoopWhy C suck here

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.. The tldr; version

MapReduce is a framework for processing embarrassingly parallelproblems across huge datasets using a large number of computers(nodes), collectively referred to as a cluster (if all nodes are on thesame local network and use similar hardware) or a grid (if thenodes are shared across geographically and administrativelydistributed systems, and use more heterogenous hardware).Computational processing can occur on data stored either in afilesystem (unstructured) or in a database (structured).MapReduce can take advantage of locality of data, processing dataon or near the storage assets to decrease transmission of data.

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.. Map

”Map” step: The master node takes the input, divides it intosmaller sub-problems, and distributes them to worker nodes. Aworker node may do this again in turn, leading to a multi-level treestructure. The worker node processes the smaller problem, andpasses the answer back to its master node.

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.. Reduce

”Reduce” step: The master node then collects the answers to allthe sub-problems and combines them in some way to form theoutput – the answer to the problem it was originally trying to solve.

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.. JSON

{"name": "John Smith","age": 25,"address": {

"streetAddress": "21 2nd Street","city": "New York""postalCode": "10021"

},"phoneNumber": [

{"type": "home","number": "212 555-1234"

},{

"type": "fax","number": "646 555-4567"

}]

}

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.. Map

The Riak way

function (v) {return [v.phoneNumber];

}

The couchDB way

function (v) {emit("phone", v.phoneNumber);

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.. Riak Search

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.. Riak Secondary Indices

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.. Riak …

Written in : Erlang & C, some Javascript

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.. Riak …

Protocol: HTTP/REST or custom binary

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.. Riak …

Tunable trade-offs for distribution and replication (N, R, W)

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.. Riak …

Pre - and post-commit hooks in JavaScript or Erlang, forvalidation and security.

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.. Riak …

Map/reduce in JavaScript or Erlang

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.. Riak …

Links & link walking: use it as a graph database

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.. Riak …

Secondary indices: but only one at once Large object support(Luwak)

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.. Riak …

Comes in ”open source” and ”enterprise” editions

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.. Riak …

Full-text search, indexing, querying with Riak …Search server (beta)

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.. Riak …

In the process of migrating the storing backend from ”Bitcask” toGoogle ”LevelDB”

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.. Riak …

Masterless multi-site replication replication and SNMP monitoringare commercially licensed

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.. Riak …

Best used: If you want something Cassandra-like (Dynamo-like),but no way you’re gonna deal with the bloat and complexity. If youneed very good single-site scalability, availability andfault-tolerance, but you’re ready to pay for multi-site replication.

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.. Riak …

For example: Point-of-sales data collection. Factory controlsystems. Places where even seconds of downtime hurt. Could beused as a well-update-able web server.

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.. Review

Multi-node ClusteringMapReduce ProcessingIntegrated Full-Text SearchSecondary IndexingMasterless Multi-Site ReplicationLarge Object SupportImplementationArchitecture

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.. Why use Riak

ScalableRiak is built so you can add more capacity as your app or platformgrows. When you add new machines, Riak distributes dataautomatically around the cluster with no downtime and anear-linear increase in performance and throughput

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.. Why use Riak

Simple OpsRiak is the most boring database you’ll ever run in production. Nosharding required, just horizontal scaling and straight-forwardcapacity planning. The same operational tasks apply to smallclusters and large clusters. More machines does not mean moreops.

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.. Why use Riak

MasterlessA Riak cluster is masterless. No node is special and any node canhandle requests for any other node in the cluster. All requests toRiak happen concurrently and developers don’t have to spend timeworrying about read/write locks or single points of failure.

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.. Why use Riak

Fault TolerantDecide how many replicas of the data you want (start at 3). Ifnodes go down, requests are routed transparently to other nodes.Riak uses proven architectural principles like hinted handoff andread repair so you can always write and read data, even in failureconditions.

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.. Why use Riak

Complex QueriesIn addition to key/value access to your data, Riak has built-insupport for MapReduce, Full Text Search, and Secondary Indexes,giving developers various ways to store and query their data.

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.. Why use Riak

Flexible APIsRiak is equipped with fully-featured HTTP and Protocol BuffersAPIs, with support for both of these transports in all of oursupported client libraries. You can also write your own client layerto wrap our APIs if your use case or preference calls for it.

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.. Why use Riak

1000s of UsersComcast, Yammer, Voxer, Boeing, BestBuy, SEOMoz, Joyent,Kiip, DotCloud, Formspring, GitHub, and the Danish Governmentare just a few of the thousands of startups and enterprises thathave deployed Riak.

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.. Who uses it and why?

github git.iocomcast Internal object storageyammer NotificationsDISQUS analytics

AOL 1.5 billion data objects per dayMozilla User reviews

joyent, best buy …

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.. Why use Riak

Language SupportBasho and the Riak Community maintain libraries for most majorlanguages including Java, Node.js, Python, Ruby, PHP, C/C++,and many more. All the client code, like the core Riak code, isavailable on GitHub.

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.. Why use Riak

Powerful CommunityThe Riak community is composed of smart, passionate hackerswho are contributing code, support, and evangelism every day.There are hundreds of companies and individuals testing, breaking,running, and building Riak.

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Questions?