Meetup core concepts-erick-ramirez-20150729

Cassandra Core Conceptsand why Netflix runs Cassandra on the cloud Erick Ramirez @flightc, DataStax Engineering

Erick Ramirez© 2015 DataStax, All Rights Reserved.

@flightc

Welcome

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• Introducing Cassandra • Why Netflix runs Cassandra on the cloud • Feel free to ask questions


@flightc

Relational data model

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• Normalised schema, table joins, ACID • Joins are very expensive on billions of rows • Sharding tables across systems is complex • Performance preferred over “always on” • Requires massive high-end systems


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Big data requirements

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• Distribute data across multiple nodes • Relaxed consistency • Relaxed schema • Scale, scale, scale!


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NoSQL landscape

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• Graph, Key-value, Document, Column family • Consistency - same result regardless of node • Availability - high read/write volumes • Partition tolerance - survive network isolation


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CAP theorem

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What is Cassandra?

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• Massively scalable NoSQL database • Fully distributed, no single-point-of-failure • Open sourced by Facebook • Linear horizontal scaling


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Modelling Cassandra

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• Use Cassandra Query Language (CQL) • Similar SQL-like approach

• CREATE, ALTER, DROP • SELECT, INSERT, UPDATE, DELETE


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Modelling Cassandra

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CREATE TABLE users ( userid text, name text, email text, PRIMARY KEY (userid));


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Why Cassandra

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• All nodes are the same - no SPOF • Real-time, durable writes • Linear scaling on commodity servers • Real-time replication across data centres • Always on - no offline operation • Because you have a scale problem


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Why not Cassandra

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• RDBMS excels in ACID transactions • You need to justify your purchase of massive

high-end servers


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Common use cases

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• Personalisation/recommendations (Netflix,ebay) • Messaging (Instagram) • IoT (Riptide IO) • Fraud detection (Barracuda) • Playlists and collections (Spotify) • Graph (SpotRight)


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A Cassandra cluster

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Cassandra Summit 2015

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academy.datastax.com

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@flightc

Thank you

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• Erick Ramirez • @flightc

Technology

Meetup core concepts-erick-ramirez-20150729