sridhar@10gen.com, @snanjund

October 26, 2012

Sridhar Nanjundeswaran, 10gen

#mongodbbangalore

Roadmap

Recent Release History

2.2

Aug ‘12

2.4

winter ‘12

2.0

Sept ‘11

1.8

March ‘11

Journaling

Sharding and

Replica set

enhancements

Spherical geo

search

Index enhancements

to improve size and

performance

Authentication with

sharded clusters

Replica Set

Enhancements

Concurrency

improvements

Aggregation

Framework

Multi-Data Center

Deployments

Improved

Performance and

Concurrency

2.2 Overview

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/

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

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

{

title : "my tech blog" ,

author : "bob" ,

tags : [ "fun" , "good" , "tech" ] ,

}

{

title : "cool tech" ,

author : "jim" ,

tags : [ "awesome" , "tech" ] ,

}

Example – For each "tag", list the authors

db.blogs.aggregate(

{ $project : {

author : 1,

tags : 1,

} },

{ $unwind : "$tags" },

{ $group : {

_id : { tags : "$tags" },

authors : { $addToSet : "$author" }

} }

);

Aggregate Command

{

"result" : [

{

"_id" : {

"tags" : "tech"

},

"authors" : [

"jim",

"bob"

]

},

Results

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 } )

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"

);

Read Preferences

• Mode – PRIMARY, PRIMARY_PREFERRED

– SECONDARY, SECONDARY_PREFERRED

– NEAREST

• Tag Sets – Uses Replica Set tags

– Passed Tag is used to find matching members

2.4 and Beyond

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)

Ongoing Work

• Collection / Extent level locking

• Field level authorization

• Auditing

• Full-text query

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/