Intro to Datomic datomic.com @stuartsierra thinkrelevance.com - PowerPoint PPT Presentation

Intro to Datomic datomic.com @stuartsierra thinkrelevance.com

What is Datomic?

What is Datomic? • A new database • Distributed reads • ACID transactions

What is Datomic? • Non-relational data model • Incorporates time • Declarative query language

Where can I use it? • Runs on the JVM • Peer library: Java and Clojure • ReST -ful API for non-JVM languages

Datomic Free Edition • Always free, redistributable • 1 transactor , up to 2 peers • Local memory or filesystem storage • Easy migration to Datomic Pro

Datomic Pro Edition • License by number of peers • High-availability transactor • Multiple distributed storage services • Integrated memcached

Data Model

Fact • One piece of information • About one thing • At a specific point in time • An immutable value

Database • A collection of facts • At a specific point in time • An immutable value

Entity • A collection of facts about one thing • Can be viewed as a map • Traversable as a graph

Fact = Datom Entity Attribute Value Time 21005 :name "Stuart" 400 21005 :nerd-level 6.8 400 21005 :name "Frodo" 421 21005 :nerd-level 9.6 421

Database as of now Entity Attribute Value Time 21005 :name "Stuart" 400 21005 :nerd-level 6.8 400 21005 :name "Frodo" 421 21005 :nerd-level 9.6 421

Database as of t=400 Entity Attribute Value Time 21005 :name "Stuart" 400 21005 :nerd-level 6.8 400 21005 :name "Frodo" 421 21005 :nerd-level 9.6 421

Database as History Entity Attribute Value Time 21005 :name "Stuart" 400 21005 :nerd-level 6.8 400 21005 :name "Frodo" 421 21005 :nerd-level 9.6 421

Datomic Architecture

Datomic Components Peer Library Transactor Storage Service

Peer Library Your Application • Included in your app Peer • Executes queries locally Library Transactor Storage Service

Peer Library Your Application • Reads data from storage Peer • Caches locally Library cache Transactor Storage Service

Scale Horizontally Your Application Your Application Your Application Peer Peer Peer Library Library Library cache cache cache Transactor Storage Service

Transactor Your Application Peer Library • Standalone system • Scales vertically Transactor Storage Service

Transactor Your Application Peer Library • Standalone system • Hot standby for failover Transactor Storage Service

Transactor Your Application Peer Library • Coordinates writes • Guarantees ACID transactions Transactor Storage Service

Transactor Your Application Peer Library • Writes transaction log to storage • Generates indexes Transactor Storage Service

Transactor Your Application Your Application Your Application Peer Peer Peer Library Library Library cache cache cache • Broadcasts live updates Transactor Storage Service

Storage Your Application Peer Library • Provided as a service • Many different back-ends Transactor Storage Service

Local Storage Your Application Peer Library • Memory • Filesystem Transactor Storage Service

Nearby Storage Your Application Peer Library • SQL database PostgreSQL Transactor Storage Service

Distributed Storage Your Application • DynamoDB Peer • Infinispan Library • Riak • Couchbase Transactor Storage Service

Datomic Components Your Application Your Application Your Application Peer Peer Peer Library Library Library Transactor Storage Service

ACID Writes Your Application Your Application Your Application Peer Peer Peer Library Library Library Transactions Transactor Storage Service Transactions & Indexes

Live Updates Your Application Your Application Your Application Peer Peer Peer Library Library Library Live updates Transactor Storage Service

Distributed Reads Your Application Your Application Your Application Peer Peer Peer Library Library Library Reads Transactor Storage Service

Local Caches Your Application Your Application Your Application Peer Peer Peer Library Library Library cache cache cache Reads Transactor Storage Service

Shared Memcached Your Application Your Application Your Application Peer Peer Peer Library Library Library cache cache cache Reads Memcached Transactor Storage Service

Datomic.com • @datomic_team • Google Group “Datomic” • @stuartsierra • thinkrelevance.com • clojure.com