1. #mongodbbangalore
Roadmap
Sridhar Nanjundeswaran, 10gen
sridhar@10gen.com, @snanjund
October 26, 2012

2. Recent Release History
1.8 2.0 2.2 2.4
March ‘11 Sept ‘11 Aug ‘12 winter ‘12
Journaling Index enhancements Aggregation
Sharding and to improve size and Framework
Replica set performance Multi-Data Center
enhancements Authentication with Deployments
Spherical geo sharded clusters Improved
search Replica Set Performance and
Enhancements Concurrency
Concurrency
improvements

3. 2.2 Overview

4. 2.2 Release August 2012
• Concurrency: yielding + db level locking
• New aggregation framework
• TTL Collections
• Improved free list implementation
• Tag aware sharding
• Read Preferences
• http://docs.mongodb.org/manual/release-notes/2.2/

5. Yielding and DB Locking
• Improved yielding on page fault
• Breaking down the global level lock
– Lock per Database in 2.2
– Lock per Collection post 2.2

6. Aggregation Framework
• Pipeline model (a bit like unix pipes)
– Like a "group by"
– Operators
• $project, $group, $match, $limit, $skip, $unwind, $sort
– Expressions
• Logical Expressions: $and, $not, $or, $cmp ...
• Math Expressions: $add, $divide, $mod ...
• String Expressions: $strcasecmp, $substr, $toLower ...
• Date/Time Expressions: $dayOfMonth, $hour...
• Multi-Expressions: $ifNull, $cond
• Use Cases: Real-time / inline analytics

7. Example – For each "tag", list
the authors
{
title : "my tech blog" ,
author : "bob" ,
tags : [ "fun" , "good" , "tech" ] ,
}
{
title : "cool tech" ,
author : "jim" ,
tags : [ "awesome" , "tech" ] ,
}

8. Aggregate Command
db.blogs.aggregate(
{ $project : {
author : 1,
tags : 1,
} },
{ $unwind : "$tags" },
{ $group : {
_id : { tags : "$tags" },
authors : { $addToSet : "$author" }
}}
);

9. Results
{
"result" : [
{
"_id" : {
"tags" : "tech"
},
"authors" : [
"jim",
"bob"
]
},

10. Time to Live (TTL)
• Auto expire data out of a collection
• Must be on a date datatype
• Single value is evaluated
• Use Cases: data retention, cache expiration
db.events.ensureIndex(
{ "timestamp": 1 },
{ expireAfterSeconds: 3600 } )

11. Tag Aware Sharding
• Distribute data based on a Tag
• Use Cases: Locality for Data by Data Center
sh.addShardTag("shard0000", "dc-emea")
sh.addTagRange("mydb.users",
{ country: "uk"}, { country: "ul"},
"dc-emea"
);
sh.addTagRange("mydb.users",
{ country: "by"},{ country: "bz"},
"dc-emea"
);

12. Read Preferences
• Mode
– PRIMARY, PRIMARY_PREFERRED
– SECONDARY, SECONDARY_PREFERRED
– NEAREST
• Tag Sets
– Uses Replica Set tags
– Passed Tag is used to find matching members

13. 2.4 and Beyond

14. 2.4 Highlights
• Security
– SASL, Kerberos, Additions to privileges and auditing
• Hash-based Sharding
• Geospatial Indexing: query intersecting polygons
• Aggregation framework: faster and more features
• V8, background secondary indexing, replica set flapping
• Distribute non-sharded collections throughout cluster
• MMS running in your own data center (separate)

15. Ongoing Work
• Collection / Extent level locking
• Field level authorization
• Auditing
• Full-text query

16. What can I do?
• MongoDB is a community driven product
– Use the product
– Log feature requests
– Vote for existing features
• Join your local meetup
– http://www.meetup.com/MongoDB-Bangalore-User-
Group/