1. Superficial MongoDB
charsyam@naver.com

2. MongoDB
NoSQL
Document
BSON

3. Document-Oriented Storage
Full Index Support
Replication & High Availability
Auto Sharding
Querying
Fast In-Place Updates
Map/Reduce
GridFS

4. Document-Oriented Storage
Full Index Support
Replication & High Availability
Auto Sharding
Querying
Fast In-Place Updates
Map/Reduce
GridFS

5. Document-Oriented
> db.users.insert( { _id : "alex", name: { first:"Alex", last:"Benisson" }, karma : 1.0 } )
> db.posts.findOne() {
_id : ObjectId("4e77bb3b8a3e000000004f7a"),
when : Date("2011-09-19T02:10:11.3Z",
author : "alex",
title : "No Free Lunch",
text : "This is the text of the post. It could be very long.",
tags : [ "business", "ramblings" ],
votes : 5,
voters : [ "jane", "joe", "spencer", "phyllis", "li" ],
comments : [
{ who : "jane", when : Date("2011-09-19T04:00:10.112Z"),
comment : "I agree." },
{ who : "meghan", when : Date("2011-09-20T14:36:06.958Z"),
comment : "You must be joking. etc etc ..." } ] }

6. Full-Index Support
> db.things.ensureIndex({j:1});
> db.things.ensureIndex({"address.city": 1})
> db.things.ensureIndex({j:1, name:-1});
> db.factories.insert( { name: "xyz", metro: { city: "New York", state: "NY" } } );
> db.factories.ensureIndex( { metro : 1 } ); // this query can use the above index: >
> db.factories.find( { metro: { city: "New York", state: "NY" } } );
// this one too, as {city:"New York"} < {city:"New York",state:"NY"}
> db.factories.find( { metro: { $gte : { city: "New York" } } } );
// this query does not match the document because the order of fields is significant
> db.factories.find( { metro: { state: "NY" , city: "New York" } } );

7. Replication
Asynchronous Replication

8. HA & FailOver
Only Write to Primary
Can read from Secondary
Op Ordinal:
Increasing ordinal to represent each operation
Using Server ID + Op Ordinal

9. Picking Primary
1. Get Max LocalOpOrdinal from each Server
2. if a majority of servers are not up (from
this server's POV), remain in Secondary
mode and stop.
3. if the last op time seems very old, stop
and await human intervention.
4. else, using a consensus protocol, pick the
server with the highest maxLocalOpOrdinal
as the Primary.

10. TIPs.

11. Use 64bit Machine
MongoDB Use Memory-Mapped File
In 32bit. DB Size can’t over 2.5GB
MongoDB is needed Big Memory

12. Use Replica Set
Use Replica Set and Journaling

13. Use Lastest Version
2.0.2 is better than 1.8.x
MongoDB has global Lock
1.8.x uses global Write Lock
2.0.x uses write with yield.
Not supports db or collection lock

14. Use Big Memory
Disk Op is slower than
Memory Op

15. Shard

16. Shard Architecture

17. Basic
Data is split up into Chunks
Chunk: 64mb or 100,000 objects
Replication unit is chunk.
Chunk Count > 9

18. Mongod
Data Store
Replica Set(3 mongod)

19. Mongos
Proxy
StateLess
Routing to Shard

20. Mongod configSvr
mongod
Can’t use Replica Set or M/A
1(test) or 3(real)

21. Mongod configSvr
Changes are made with 2PC
If any are down, meta data
goes read only
System is online as long as 1/3
is up

22. Use Scale Up than Sharding
Difficult to find good Shard Key.
Not Support Data Center
awareness
Add memory and hdd, ssd

23. Object Id_

24. Object Id_
12 bytes

25. Replica Set

26. Operations
Default: Write/read operation
goes to master
Can read from slaves.

27. Thank you!