Introduction to RethinkDB : Hack Reactor

Transcript

1. RethinkDB The database for the realtime web Hack Reactor San Francisco, CA June 4, 2015
2. Jorge Silva @thejsj Developer Evangelist @ RethinkDB
3. Introduction What is RethinkDB?
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
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
6. RethinkDB Structure Database → Table → Document MySQL: Database → Table → Row MongoDB: Database → Collection → Document
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" }, ], ... }
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
9. Differences with MongoDB • RethinkDB supports joins and subqueries • MongoDB has a traditional query- response model. You can't subscribe to queries.
10. Introduction to ReQL RethinkDB Query Language
11. Introduction to ReQL • ReQL embeds natively into your programming language • Compose ReQL queries by chaining commands
12. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Number of unique last names
13. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Access a database table
14. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Isolate a document property
15. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Consolidate duplicate values
16. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Display the number of items
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"})
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
19. Running Queries http://github.com/thejsj/rethinkdb-quickstart
20. http://rethinkdb-chat.thejsj.com:10001/ Running Queries
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
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
23. Realtime Updates Working with Changefeeds
24. Subscribe to change notifications on database queries Changefeeds
25. r.table("users").changes() Track changes on the users table Changefeeds
26. Changefeeds • The changes command returns a cursor that receives updates • Each update includes the new and old value of the modified record
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 }
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', ... } }
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' } }
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:
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:
32. Using Changefeeds http://github.com/thejsj/rethinkdb-quickstart
33. http://realtime-photo.thejsj.com/ Sample Application
34. Cluster Configuration Sharding and replication
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
36. Add a Server to a Cluster $ rethinkdb --join server:29015 >
37. Clustering
38. Additional Resources • RethinkDB website:
 http://rethinkdb.com • RethinkDB cookbook:
 http://rethinkdb.com/docs/cookbook • RethinkDB installation:
 http://rethinkdb.com/docs/install/
39. Questions?