1. MongoDB Intro

2. What is MongoDB?
▪ It’s a no-sql database.
▪ Document Oriented
▪ Data stored as BSON

3. Where you should use MongoDB
▪ If your application is write intensive: MongoDB has
super-fast writes.
– You can use capped collection for logging as well
▪ In built support for geo-spatial indexes.
▪ When the schema is not carved in stone. Really
helpful in Agile development.

4. Where you should use
MongoDB(cont)
▪ No migrations required in MongoDB
▪ In built support for sharding.
▪ Support for many languages

5. Faster writes
▪ Fan-out newsfeed

6. Faster writes
▪ Fan-out newsfeed.
▪ Foursquare does ~80 checkins/sec(1).
▪ Gotchas
– Lock at database level
▪
(1) https://docs.google.com/presentation/d/1q4R3F0AnWN-MQZqbysZ92nZ4_OC7bRzUCWfbmeHHcQQ/pub?start=false&loop=false&delayms=3000&pli=1#slide=id.ga365b3_0_5

7. Faster writes
▪ Fan-out newsfeed.
▪ Foursquare does ~80 checkins/sec(1).
▪ Gotchas
– Lock at database level
▪
(1) https://docs.google.com/presentation/d/1q4R3F0AnWN-MQZqbysZ92nZ4_OC7bRzUCWfbmeHHcQQ/pub?start=false&loop=false&delayms=3000&pli=1#slide=id.ga365b3_0_5

8. Capped collection for logging
▪ Collection == table
▪ Can be time based or size based

9. geo-spatial indexes
▪ Place your Domino’s order to the nearest outlet?

10. geo-spatial indexes
▪ db.collection('places').find(
{loc: {$near: [50,50], $maxDistance: 10}}).

11. Flexible schema
"_id" : ObjectId("526a55f14162689cbc0c0000"),
"first_name" : "First Name 0",
"last_name" : "last Name 0",
"add" : "Address number is 0",
"company" : "company 0",
"employee_id" : "0"
"_id" : ObjectId("526a55f14162689cbc0c0001"),
"first_name" : "First Name 1",
"last_name" : "last Name 1",
"add" : "Address number is 1",
"company" : "company 1",
"employee_id" : “1“,
“is_external” : “true”

12. Flexible schema
▪ In mySQL, extra space for “is_external” as “nil” for
most of the rows which leads to the wastage of
space.
▪ No need for the migration

13. No migration
▪ Migrations are expensive and time consuming. It
increase proportionally to the size of your table
▪ How does a migration happen
– Create a temp copy of the table with the
migration
– Delete the old table
– Make temp copy permanent

14. Sharding support
Source: http://www.slideshare.net/mdirolf/introduction-to-mongodb

15. In-built support for sharding.