This document summarizes the new features in version 2.6 of MongoDB, including: 1) Aggregation cursors that allow controlling batch size and iterating over aggregation results. 2) A maxTimeMS option that sets a timeout for queries and commands. 3) New and enhanced update operations like $mul, $bit, $min/$max, $currentDate, and $push enhancements. 4) A new security model with roles and rights to customize access control.

1. What’s new in 2.6
DriverTeam Lead,Node.js driver,MongoDB INC
Christian Kvalheim
#mongodb

2. Me
• Driver Team Lead
• Node.js driver developer
• @christkv
• http://www.christiankvalheim.com

3. Agenda
• Aggregation Cursors
• maxTimeMS
• New or Enhanced update operations
• New Security Model
• Ordered/Unordered Bulk Operations
• Background index building on secondaries
• parallelCollectionScan command

4. Aggregation Cursors

5. Aggregation Cursors
• Aggregation framework can now return a cursor
var test = db.getSisterDB('test');!
test.t.drop();!
!
for(var i = 0; i < 100; i++) {!
db.t.insert({a:i});!
}!
!
var c = test.t.aggregate([{$match: {}}], {cursor: { batchSize:1 }});!
!
while(c.hasNext()) {!
print(c.next().a);!
}!

6. Aggregation Cursors
• You can control the behavior of the aggregation cursor
passing in the cursor option with the batchSize
> db.runCommand({aggregate: "t", pipeline: [], cursor: {batchSize: 1}!
! , allowDiskUse: true})!
{!
! "cursor" : {!
! ! "id" : NumberLong("39465949628"),!
! ! "ns" : "test.t",!
! ! "firstBatch" : [!
! ! ! {!
! ! ! ! "_id" : ObjectId("532808ea4be168cc8e9dd7dd"),!
! ! ! ! "a" : 0!
! ! ! }!
! ! ]!
! },!
! "ok" : 1!
}!

7. Aggregation Cursors
• Cursor id is just a normal MongoDB cursor meaning it
works like other cursors using the wire protocol call
getMore.

8. maxTimeMS

9. maxTimeMS
• Ever wanted to set a specific query or command
timeout ?
• maxTimeMS is what you’ve been looking for.
> db.t.find({"$where": "sleep(1000)"}).maxTimeMS(50)!

10. New or Enhanced update
operations

11. New or Enhanced update operations
• $mul
• $bit
• $min/$max
• $currentDate
• $push enhancements

12. $mul
var test = db.getSisterDB('test');!
test.t.drop();!
!
db.t.insert({ _id: 1, item: "ABC", price: 10.99 });!
!
db.t.update({ _id: 1 },!
{ $mul: { price: 1.25 } });!
!
print(db.t.findOne({_id:1}).price);!

13. $bit
• supports and/or/xor (xor is new)
var test = db.getSisterDB('test');!
test.t.drop();!
!
db.t.insert({ _id: 1, expdata: NumberLong(1) });!
!
db.t.update({ _id: 1 },!
{ $bit: { expdata: { xor:
NumberInt(5) } } })!
!
print(db.t.findOne({_id:1}).expdata);!

14. $min/$max
var test = db.getSisterDB('test');!
test.t.drop();!
!
db.t.insert({ _id: 1, desc: "crafts", !
dateEntered: ISODate("2013-10-01T05:00:00Z"),!
dateExpired: ISODate("2013-10-01T16:38:16Z")!
});!
!
db.t.update({ _id: 1 }, {!
$min: { dateEntered: new Date("2013-09-25") }!
})!
!
print(db.t.findOne({_id:1}).dateEntered);!

15. $currentDate
var test = db.getSisterDB('test');!
test.t.drop();!
!
db.t.insert({ _id: 1, !
! status: "a", !
! lastModified: ISODate("2013-10-02T01:11:18.965Z") });!
!
db.t.update({ _id: 1 }, {!
! $currentDate: {!
! ! lastModified: true,!
! ! lastModifiedTS: { $type: "timestamp" }},!
! $set: { status: "D" }!
});!
!
printjson(db.t.findOne({_id:1}));!

16. $push enhancements
var test = db.getSisterDB('test');!
test.t.drop();!
!
db.t.insert({ "_id" : 1, "scores" : [50,60,70,100 ]});!
!
db.t.update({ _id: 1 }, !
! { $push: { scores: {!
! ! ! $each: [ 20, 30 ],!
! ! ! $position: 2!
! ! }!
! }!
});!
!
printjson(db.t.findOne({_id:1}));!

17. New Security Model

18. New Security Model
• Now with
• Roles
• Rights
• You can customize the roles and rights to your liking.
• Subscription Edition also includes
• LDAP
• X509 authentication

19. New Security Model - Create Role Ex
var admin = db.getSisterDB('admin');!
admin.createRole({!
role: "myClusterwideAdmin",!
privileges:!
[!
{ resource: { cluster: true }, !
! actions: [ "addShard" ] },!
{ resource: { db: "config", collection: "" }, !
! actions: [ "find", "update", "insert" ] },!
{ resource: { db: "users", collection: "usersCollection" }, !
! actions: [ "update" ] },!
{ resource: { db: "", collection: "" }, !
! actions: [ "find" ] }!
],!
roles:!
[!
{ role: "read", db: "admin" }!
],!
writeConcern: { w: "majority" , wtimeout: 5000 }!
})!

20. Ordered/Unordered Bulk
Operations

21. Ordered/Unordered Bulk Operations
var test = db.getSisterDB('test');!
test.t.drop();!
!
var bulk = db.t.initializeOrderedBulkOp();!
bulk.insert({a:1});!
bulk.find({a:1}).update({$set: {b:1}});!
bulk.find({a:2}).upsert().update({$set: {b:1}});!
bulk.find({a:1}).remove();!
var result = bulk.execute({w:1});!
printjson(result);!

22. Ordered/Unordered Bulk Operations
• New BulkAPI shared across drivers and shell
• Uses new write Commands underneath the covers
• Splits up documents into batches
• Write Commands is the future of writing for MongoDB
• w:0 semantics is no result details when using write
commands

23. Ordered/Unordered Bulk Operations
• Ordered
• Execute all operations in the order they where
entered and fail on first write error
• Guarantees order of execution
• Unordered
• Executes all operations out of order and potentially
in parallel.Does not stop on error.
• Does not Guarantee order of execution

24. Background index building on
secondaries

25. Background index building on secondaries
• Previously only available on primary
• Could cause secondaries to hang
• Was not practical in many situations
• Secondaries can now build indexes in background
• Can also restart partially build indexes on instance
termination and restart

26. parallelCollectionScan command

27. parallelCollectionScan command
• Split collection into multiple cursors
• Read in parallel from the collection
• No matching semantics (it’s for pure dumping
purposes only)

28. parallelCollectionScan command
var test = db.getSisterDB('test');!
test.t.drop();!
!
var bulk = db.t.initializeOrderedBulkOp();!
for(var i = 0; i < 100000; i++) {!
! bulk.insert({a:i});!
};!
!
var result = bulk.execute({w:1});!
result = test.runCommand({!
! ! parallelCollectionScan: 't'!
! ,! numCursors: 4!
});!
!
printjson(result);!

29. ThankYou
DriverTeam Lead,Node.js driver,MongoDB INC
Christian Kvalheim
#mongodb