@muc_rubyshift 11/09/2013

1. Anna Bulenkova
@povergo
Software Developer
@
JetBrains
Brains
Brains
Brains
Brains
Brains

2. MongoDB

4. How to look like
a model?
a model?

5. A long time ago in a
galaxy far, far away

8. Wow!
It’s schema-free!
It’s schema-free!

9. Say bye-bye to

10. •Normalization
Say bye-bye to

11. •Normalization
•Joins
Say bye-bye to

12. •Normalization
•Joins
•Design issues
Say bye-bye to

13. •Normalization
•Joins
•Design issues
•Transactions
Say bye-bye to

14. Something wrong?

15. Document
=
{ key -> value }
{ key -> value }
{ key -> value }

16. Document-oriented
!=
schema-free
schema-free
schema-free

18. Collection

19. BSON

20. "x16x00x00x00x02hellox
00
x06x00x00x00worldx00x
00"

21. Outside MongoDB
world?

22. MongoDB
•Win/OS X/*nix
•JavaScript

23. user = { name : "Foo" }
db.testData.insert(user)
db.testData.find()
db.testData.find()
db.testData.find()

24. { "_id" :
ObjectId("51a7dc7b2cacf40b79990bf7"),
"name" : "Foo" }
"name" : "Foo" }

26. •API
•Aggregation
•Indexes
•Replication
•Sharding

27. A little bit of
ActiveRecord?
ActiveRecord?

28. Mongoid

29. $ gem install mongoid

30. Configuration

31. Model

32. Associations

33. Embedded 1-1

34. Embedded 1-N

35. I want my
relationship back!

36. Referenced 1-1

37. Referenced 1-N

38. Referenced N-N

39. # The band document.
{
"_id" : ObjectId("4d3ed089fb60ab534684b7e9"),
"tag_ids" : [ ObjectId("4d3ed089fb60ab534684b7f2") ]
}
# The tag document.
{
"_id" : ObjectId("4d3ed089fb60ab534684b7f2"),
"band_ids" : [ ObjectId("4d3ed089fb60ab534684b7e9") ]
}
}
}
}
}
}
}
}
}
}
}
}
}
}

40. $gem install mongoid_rails_migrations

42. It’s magical...

43. What a twist!

44. Where the hell
are
transactions?

45. MongoDB does not have support for
traditional locking or complex
transactions with rollback. MongoDB
aims to be lightweight, fast, and
predictable in its performance. This
is similar to the MySQL MyISAM
autocommit model. By keeping
transaction support extremely simple,
MongoDB can provide greater
performance especially for
partitioned or replicated systems
with a number of database server
processes.

46. limit
16MB

47. Global write
lock
2.0pre
2.0pre

48. DB level lock
2.2
2.2

49. No joins
->
Many queries
Many queries
Many queries

50. Too many
queries?
->
Redesign
Redesign
Redesign

51. Indeed
schemaless?

52. Journaling
100ms
100ms

53. Data loss
after
replication
replication
replication

54. Sharding delay

55. Unencrypted
traffic

56. Side effects may
include...
Problems working on 32-bit, large data
storage problems, write falures, no error
value return, sophicticated schema design,
limited update operation, case sensitive
queries, type sensitive fields, write
locks, replica sets restrictions,
unexpected data loss, sharding size
limitations, no transactions, nausea,
going back to RDBMS

57. It’s supported
in
RubyMine
Mine

61. Any questions?

62. Thank you!