New to MongoDB? This talk will introduce the philosophy and features of MongoDB. We’ll discuss the benefits of the document-based data model that MongoDB offers by walking through how one can build a simple app to store books. We’ll cover inserting, updating, and querying the database of books. This session will jumpstart your knowledge of MongoDB development, providing you with context for the rest of the day's content.

1. #mongodb
Build your first app;
an introduction to MongoDB
Christian Amor Kvalheim
Developer Experience Team Lead, MongoDB

2. Christian Kvalheim
• Team Lead MongoDB Drivers
• Node.js driver developer
• Been using MongoDB for 5 years
• Working at MongoDB last 3 years

3. What is MongoDB?

4. MongoDB is a ___________
database
• Document
• Open source
• High performance
• Horizontally scalable
• Full featured

5. Document Database
• Not for .PDF & .DOC files
• A document is essentially an associative array
• Document = JSON object
• Document = PHP Array
• Document = Python Dict
• Document = Ruby Hash
• etc

6. Open Source
• MongoDB is an open source project
• On GitHub
• Licensed under the AGPL
• Started & sponsored by MongoDB Inc
• Commercial licenses available
• Contributions welcome

7. High Performance
• Written in C++
• Extensive use of memory-mapped files
i.e. read-through write-through memory caching.
• Runs nearly everywhere
• Data serialized as BSON (fast parsing)
• Full support for primary & secondary indexes
• Document model = agile development

8. Database Landscape

9. Full Featured
• Flexible schema
• Rich ad-hoc queries
• Real time aggregation
• Strongly consistent
• Geospatial features
• Built-in automatic failover
• Horizontally scalable reads/writes
• Support for most programming languages

10. mongodb.org/downloads

11. Running MongoDB
$ tar zxf mongodb-osx-x86_64-2.6.4.tgz
$ cd mongodb-osx-x86_64-2.6.4/bin
$ mkdir –p /data/db
$ ./mongod

12. Mongo Shell
$ mongo
MongoDB shell version: 2.6.4
connecting to: test
> db.test.insert({text: 'Welcome to MongoDB'})
> db.test.find().pretty()
{
"_id" : ObjectId("51c34130fbd5d7261b4cdb55"),
"text" : "Welcome to MongoDB"
}

13. Building an App with
MongoDB

14. Terminology
RDBMS MongoDB
Table, View ➜ Collection
Row ➜ Document
Index ➜ Index
Join ➜ Embedded Document
Foreign Key ➜ Reference
Partition ➜ Shard

15. Let’s Build a Monitoring System

16. First step in any application is
Determine basic requirements

17. Basic Monitoring Requirements
• Data generated at per-second intervals
• Metrics to capture (ex. CPU, memory, IO)
• Document structure for fast writes and easy reads

18. In a relational base app
We would start by doing schema
design

19. Relational Schema Options
CPU Metrics
Memory Metrics
IO Metrics
Events
• Timestamp
• CPU metrics
• Memory metrics
• IO metrics
Or

20. In a MongoDB based app
We start with a generic model
and let the documents evolve

21. MongoDB Document Modeling
Events
Timestamp (min)
CPU []
• Second
• Metric
Memory []
• Second
• Metric
IO []
• Second
• Metric

22. Working With MongoDB

23. Start with the Mongo Shell
$ mongo
MongoDB shell version: 2.6.4
connecting to: test
>
Full Javascript shell

24. Switch to Your DB
> use monitoring
switching to db monitoring
DB files are created once you save a
document

25. Create an Empty Event
> var event = {
ts: ISODate(“2014-09-16T09:00:00”),
cpu: [ 0, 0, …, 0 ],
memory: [ 0, 0, …, 0 ],
io: [ 0, 0, …, 0 ],
}
Insert zeroed-out arrays to fill in later

26. Insert the Event
> db.events.insert(event)
No collection creation necessary

27. Find One Record
> db.events.findOne()
{
"_id" : ObjectId("50804d0bd94ccab2da652599"),
”ts" : ISODate(“2014-09-16T09:00:00”),
”cpu" : [ 0, 0, …, 0 ],
”memory" : [ 0, 0, …, 0 ],
“io” : [ 0, 0, …, 0 ]
}

28. How do you capture events?
Serve
r
Serve
r
Serve
r
MongoD
B
memory
interaction
interaction
interaction

29. Adding a New Event
> db.events.update(
{ ts: ISODate(“2014-09-16T09:00:00”) }
{ $set: {
“cpu.0” : 50,
“memory.0”: 1500,
“io.0”: 10 }
}
)
Use atomic in-place updates to add metric values

30. How do you plot charts?

31. Finding an Hour of Events
> db.events.find({
ts: {
$gte: ISODate(“2014-09-16T09:00:00”),
$lt: ISODate(“2014-09-16T10:00:00”)
}
}).sort({ts:1})
Find using a range and sort results
ascending

32. How do you roll up the data?
Hour Avg Cpu
0 50
1 65
2 75
3 40
4 45
5 60
6 25
… …
23 30

33. Aggregate Metrics
> db.events.aggregate([
{ $match: { ts: { $gte: date0, $lt: date1 } } },
{ $project: { _id: 0, ts: 1, cpu: 1 } },
{ $unwind: “$cpu” },
{ $group: {
_id: { $hour: “$ts” },
avg_cpu: { $avg: “$cpu” } } }
])
Use Aggregation Framework to roll up data

34. How do you scale this workload
• Replica Sets
– Add data redundancy
– Automatic failover
– Tunable durability, consistency
• Sharding
– Scale reads and writes
– Support dynamic data growth
– Automatically partitions workload
– Horizontally scalable

35. MongoDB Drivers

36. Real applications are not
built in the shell

37. MongoDB has native
bindings for over 12
languages

40. MongoDB Drivers
• Official Support for 12 languages
• Community drivers for tons more
• Drivers connect to MongoDB servers
• Drivers translate BSON into native types
• Shell is not a driver, but works like one in some ways
• Installed using typical means (npm, pecl, gem, pip)

41. docs.mongodb.org

42. Online Training at MongoDB
University

43. Suggestions for Talks
• Talk to me at Meet the Experts
– 11 am – 12 pm
– 1 pm – 2 pm
– Or catch me in the hallway
• MongoDB for the internet of things
• Socialite the Open Source Status Feed
• The Future of MongoDB Storage

44. Questions?

45. #mongodb
Thank You
Christian Amor Kvalheim
Developer Experience Team Lead, MongoDB