NoSQLUsing the right tool for the right job

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No SQL

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No SQL

Not Only/ I /I

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No SQL

Not Only/ I /I/

/

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No SQL

Not Only/ I /I/

/Relational

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Need to store some data ?

Oracle

SQL Server

Sybase

DB2

MySQL

PostgreSQL

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RDBMS are great for relational

storage !

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RDBMS may not be fully trivial…

…what a pity if you just wanted

a put / get store

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How to achievescalability and

high availabilitywith a RDMS ?

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Memcached can help to reduce the

pressure on RDBMS

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But this wasn’t enough for some

people…

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The birth of Dynamo at

Amazon.com…

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Write must ALWAYS be available Only key-value is required

Temporal unavailability is acceptableRich storage is preferred for reporting

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So they started to create their own

database that would match their

needs… Table de hachage

persistante

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So they started to create their own

database that would match their

needs…

Table de hachage

persistante

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Consistent hashing spreads keys

uniformally across the partitions

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Sharding brings scalability,

replication brings high availability

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But failures still have to be handled

efficiently…

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In case of failure of a node, the 2 other nodes serve its load

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In this configuration,

clients know only few nodes which

act as proxy to other nodes…

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Gossip protocol to let everybody know node B has failed…

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Eventual consistency…

N = Number of replicas

R = Number of read responses to wait for

W = Number of write aknowledges to wait for

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The ratio between N, R and W makes

everything…

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The ratio between N, R and W makes

everything…

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The ratio between N, R and W makes

everything…

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Key-value storesare simple…

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Several competitors…

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Riak…

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Riak…

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Document oriented databases are an evolution of key-

value stores

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MongoDB is the leader so far…

… 10gen said they are the « MySQL of

NoSQL »

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MongoDB is the leader so far…

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MongoDB is the leader so far…

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Graph databases are great to store…

graphs !

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Neo Technology is the leader so far

with Neo4j…

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Neo4j…

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Column-oriented databases have a

very particular data model…

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CassandraVs

HBase !

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Cassandra adds SuperColumns to

this model…

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Cassandra was developped at

Facebook, to store the user messages

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Now also used by Digg, Twitter, Rackspace,…

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What a model…

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An example…

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Cassandra Demo