This document summarizes Mitch Pirtle's talk about MongoDB at the jsDay 2014 conference in Verona, Italy. The talk included: an introduction to MongoDB and how it addresses the limitations of relational databases for modern web applications; a demonstration of the MongoDB console; stories about how a company successfully used MongoDB, including increased performance and faster development; and warnings about potential issues like not updating data when changing schemas and not planning for operational impacts like backups.

1. Node.js, MongoDB
and You: Part I
Mitch Pirtle
jsDay 2014, Verona Italy - @jsdayit

2. First, tell me about
yourselves.

3. New to Node?

4. Come on, be honest!

5. New to Node?

6. New to MongoDB?

7. Does your Javascript
totally suck?

8. Ok my Javascript
totally sucks.

9. Now about me.

10. Mitch Pirtle
• Recovering Joomla! founder
• Mongo Master
• Starting companies since
1995
• Musician, skate punk, football
coach
• American idiot living in Turin

11. Important Mitch Facts
• I am not cool. However I have been called perky.
• I am not Rich. My name is Mitch. Such is life.
• I am internet famous. Just to be clear:
Internet Famous + $1.50 = $1.50

12. About this talk.

13. Ok, technically there
are three talks today.

14. • Session 1: All about MongoDB (this one)!
• Session 2: All about Node.js (that’s next)
• Session 3: The coolness of both together

15. That’s a lotta
lotta stuff to
cover
STAY ALERT

16. All About MongoDB
• Brief introduction to MongoDB
• CONSOLE!
• Really cool discoveries and surprises
• Shameful admissions and painful stories

17. In The Beginning
• We had relational databases. Back then they
were called “databases” and that’s where you
stored your data.
• Primary focus: atomicity, consistency, reliability.
• Was normal to spend 6 hours. ON ONE QUERY.
• I love vacuum tubes, keep you warm in winter.
• Life was good.

18. What Happened
• Hello, Internet!
• Databases became immediate source of pain for
scale, performance
• Traffic grew, along with it came bigger
expectations, infinitely more complexity, a slew
of new platforms, and Big Data™

19. That sure looks like a
nail to me.

20. Troubled Relations
• Web languages gravitated toward objects, not
3NF entites/relations
• Size of data needed to live on more than one
physical machine
• Performance requirements needed to be far
better

21. Along came sharding
• Can split your data across multiple machines
• Also splits your query load across multiple
machines
• Like RAID for your data, right?

22. What sharding brought
along for the ride
• How do you back this stuff
up?
• How do you spread a group
query across N machines
again?
• How do you run a join query
that spans a sharded table?

23. All those hours, spent
mastering 3NF and
procedural programming

24. IMPORTANT LESSON:

25. It is REALLY hard to scale
a relational database
engine.

26. The common approach pushed
logic out of the database back
into the application tier.

27. Then why use a
relational database
in the first place?

28. Then there was…

29. The Promises of MongoDB
• Speed - crazy whack-daddy fast
• Simplicity - JSON documents FTW
• Embedded documents
• 16MB limit
• Scale - sharding, multimaster out of the box
• Yes, I said whack-daddy.

30. ENOUGH TALK
BRING ON THE CONSOLE

31. Wait, there’s more
• Fulltext: Allows for compound indexes, supports
many languages
• Sharding: You can scale collections across N
machines
• GridFS: Simple interface to store files in your
database (CONSOLE!)
• Multimaster: Replica Sets make it possible for
read slaves, failover, redundancy

32. Now some cool stories

33. Mini Case Study: Totsy
• First ecommerce site to rely on MongoDB for all
data. Everything. Even product images and
associated media.
• I suspected it would be fast.
• I suspected we could develop quickly.
(This was important, as they only let me hire one
guy.)

34. So how fast was it?

35. Launch story
• Went live with MongoDB on a quad-core
consumer grade el-cheapo machine, only 2GB
RAM.
• I was terrified.
• Over a million moms waiting for the launch.
• Upon launch, load was 0.05. Highest it ever got
was around 0.5.

36. Was development
quicker?

37. Development impact
• Simple models make for less code. There were
no sixteen-table joins, no ORM, one result had
all the data needed from a single query.!
• Less code makes for less bugs. No more six-
hour query debugging marathons. No more
learning why UNION was faster than JOIN…
• Less bugs leaves time for more code. Did I
mention they only let me hire one guy?

38. Even moar impact
• Used GridFS for all media storage.
• Allowed free MD5 checking for duplicates.
• Allowed storage of metadata per file (views,
comments, rates, whatever else we wanted).
• No need for NFS, clumsy rsync cronjobs, high
costs of NAS or iSCSI.

39. Now some sad stories.

40. The perils of schemaless
• Started prototyping quickly enough
• Made a couple changes to user model
• Made some more changes…
• WHUPS WHY FIFTEEN KINDS OF USER?!?!

41. Remember: Always
update existing data
when changing models.

42. Everything in the database!
• Backups were brutal
• Forgot to separate GridFS data from main
database
• Totally unprepared for the operational impact

43. Remember: Operational
impact BEFORE you
launch.

44. Stump the Geek™

45. Thanks!
• AboutMe
• @mitchitized - Twitter
• spacemonkey - GitHub
• LinkedIn - I’M AVAILABLE!