Introduction to RethinkDB : Hack Reactor

Transcript

1. RethinkDB
   The database for the
   realtime web
   Hack Reactor
   San Francisco, CA
   June 4, 2015
   

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2. Jorge Silva
   @thejsj
   Developer Evangelist @ RethinkDB
   

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3. Introduction
   What is RethinkDB?
   

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4. What is RethinkDB?
   • Open source database for building
   realtime web applications
   • NoSQL database that
   stores schemaless JSON documents
   • Distributed database that is easy to
   scale
   

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5. Built for Realtime Apps
   • Subscribe to change notifications
   from database queries
   • No more polling — the database
   pushes changes to your app
   • Reduce the amount of plumbing
   needed to stream live updates
   

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6. RethinkDB Structure
   Database → Table → Document
   MySQL: Database → Table → Row
   MongoDB: Database → Collection → Document
   

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7. Sample Document
   {
   "name": "Will Riker",
   "position": "Commander",
   "height": 193,
   "birthdate": Mon Aug 19 2335,
   "ships": [
   { "name": "USS Pegasus" },
   { "name": "USS Potemkin" },
   { "name": "USS Enterprise" },
   ],
   ...
   }
   

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8. Differences with Firebase
   • Firebase is a cloud service, not an
   open-source database
   • Because Firebase is not a database,
   it has limited querying abilities
   • Firebase is made to be queried
   from the browser
   

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9. Differences with MongoDB
   • RethinkDB supports joins and
   subqueries
   • MongoDB has a traditional query-
   response model. You can't
   subscribe to queries.
   

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10. Introduction to ReQL
    RethinkDB Query Language
    

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11. Introduction to ReQL
    • ReQL embeds natively into your
    programming language
    • Compose ReQL queries by
    chaining commands
    

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12. Anatomy of a ReQL Query
    r.table("users")
    .pluck("last_name")
    .distinct().count()
    Number of unique last names
    

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13. Anatomy of a ReQL Query
    r.table("users")
    .pluck("last_name")
    .distinct().count()
    Access a database table
    

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14. Anatomy of a ReQL Query
    r.table("users")
    .pluck("last_name")
    .distinct().count()
    Isolate a document property
    

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15. Anatomy of a ReQL Query
    r.table("users")
    .pluck("last_name")
    .distinct().count()
    Consolidate duplicate values
    

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16. Anatomy of a ReQL Query
    r.table("users")
    .pluck("last_name")
    .distinct().count()
    Display the number of items
    

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17. Sample ReQL Queries
    r.table("users")
    .filter(r.row("age").gt(30))
    r.table(“post")
    .eqJoin(“uId”, r.table(“users”))
    .zip()
    r.table("fellowship")
    .filter({species: "hobbit"})
    .update({species: "halfling"})
    

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18. ReQL Commands
    • Transformations: map, orderBy, skip, limit,
    slice
    • Aggregations: group, reduce, count, sum,
    avg, min, max, distinct, contains
    • Documents: row, pluck, without, merge,
    append, difference, keys, hasFields, spliceAt
    • Writing: insert, update, replace, delete
    

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19. Running Queries
    http://github.com/thejsj/rethinkdb-quickstart
    

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20. http://rethinkdb-chat.thejsj.com:10001/
    Running Queries
    

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21. Understanding ReQL
    • Client driver translates ReQL queries
    into wire protocol
    • Anonymous function must return a
    valid ReQL expression
    • In JS use e.g. the mul and gt
    commands instead of the normal
    operators
    

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22. Additional ReQL Features
    • Geospatial indexing for location-
    based queries
    • Date and time functions for time
    data
    • Support for storing binary objects
    • Execute http requests using r.http
    

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23. Realtime Updates
    Working with Changefeeds
    

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24. Subscribe to change notifications
    on database queries
    Changefeeds
    

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25. r.table("users").changes()
    Track changes on the users table
    Changefeeds
    

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26. Changefeeds
    • The changes command returns a
    cursor that receives updates
    • Each update includes the new and
    old value of the modified record
    

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27. Changefeeds
    r.table("users").changes()
    r.table("users")
    .insert({name: "Bob"})
    Changefeed output:
    {
    new_val: {
    id: '362ae837-2e29-4695-adef-4fa415138f90',
    name: 'Bob',
    ...
    },
    old_val: null
    }
    

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28. Changefeeds
    r.table("users").changes()
    r.table("users")
    .filter({name: "Bob"}).delete()
    Changefeed output:
    {
    new_val: null,
    old_val: {
    id: '362ae837-2e29-4695-adef-4fa415138f90',
    name: 'Bob',
    ...
    }
    }
    

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29. Changefeeds
    r.table("users").changes()
    r.table("users")
    .get("362ae837-2e29-4695-adef-4fa415138f90")
    .update({name: "Bobby"})
    Changefeed output:
    {
    new_val: {
    id: '362ae837-2e29-4695-adef-4fa415138f90',
    name: 'Bobby'
    },
    old_val: {
    id: '362ae837-2e29-4695-adef-4fa415138f90',
    name: 'Bob'
    }
    }
    

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30. Changefeeds
    r.table("players")
    .orderBy({index: r.desc("score")})
    .limit(3).changes()
    Track top three players by score
    Chain the changes command
    to an actual ReQL query:
    

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31. Changefeeds
    r.table("table").get(ID).changes()
    r.table("table").getAll(ID).changes()
    r.table("table").between(X, Y).changes()
    r.table("table").filter(CONDITION).changes()
    r.table("table").union(ID).changes()
    r.table("table").map(FUNCTION).changes()
    r.table("table").min(INDEX).changes()
    r.table("table").max(INDEX).changes()
    r.table("table").orderBy(INDEX)
    .limit(N).changes()
    Commands that currently
    work with changefeeds:
    

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32. Using Changefeeds
    http://github.com/thejsj/rethinkdb-quickstart
    

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33. http://realtime-photo.thejsj.com/
    Sample Application
    

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34. Cluster Configuration
    Sharding and replication
    

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35. Sharding and Replication
    • RethinkDB is designed for clustering and
    easy scalability
    • To add a new server to the cluster, just
    launch it with the join option
    • Configure sharding and replication per table
    • Any feature that works with a single
    database will work in a sharded cluster
    

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36. Add a Server to a Cluster
    $ rethinkdb --join server:29015
    >
    

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37. Clustering
    

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38. Additional Resources
    • RethinkDB website:

    http://rethinkdb.com
    • RethinkDB cookbook:

    http://rethinkdb.com/docs/cookbook
    • RethinkDB installation:

    http://rethinkdb.com/docs/install/
    

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39. Questions?
    

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