Introduction to MongoDB

Scale Hacking
Introduction to MongoDB
moshe.kaplan@brightaqua.com
http://blogs.microsoft.co.il/blogs/vprnd
http://top-performance.blogspot.com

About
2
Scale

HELLO. MY NAME IS MONGODB
Introduction
3

Who is Using mongoDB?
4

Who is Behind mongoDB

Key Value Store (with benefits)
insert
get
multiget
remove
truncate
6
<Key, Value>
http://wiki.apache.org/cassandra/API

When Should I Choose NoSQL?
Eventually Consistent
Document Store
Key Value
7
http://guyharrison.squarespace.com/blog/tag/nosql

What mongoDB is Made of?
8
http://www.10gen.com/products/mongodb

Why MongoDB?
What? Why?
JSON End to End
No Schema “No DBA”, Just Serialize
Write 10K Inserts/sec on virtual machine
Read Similar to MySQL
HA 10 min to setup a cluster
Sharding Out of the Box
LBS Great for that
No Schema None: no downtime to create new columns
Buzz Trend is with NoSQL
9

DESIGN FOR NOSQL
Introduction
10

Database for Software Engineers
Class
Subclass
Document
Subdocument

Same Terminology
Database  Database
Table  Collection
Row  Document

A Blog Case Study in MySQL
http://www.slideshare.net/nateabele/building-apps-with-mongodb

as a SW Engineer would like it to be…

INSTALLATION
Introduction
15

A free hosting environment for you

The CentOS/RHEL Way
Add to /etc/yum.repos.d/10gen.repo
[10gen]
name=10gen Repository
baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/x86_64
gpgcheck=0
enabled=1
yum –y install mongo-10gen mongo-10gen-server
The Packages:
mongo-10gen: tools
mongo-10gen-server: mongod and mongos
http://docs.mongodb.org/manual/tutorial/install-mongodb-on-red-hat-centos-or-fedora-linux/

USAGE BASICS
Introduction
18

Connect to the Database
Connect:
• > mongo
Show current database:
• >> db
Show Databases
• >> show databases;
Show Collections
• >> show collections;

Databases Manipulation: Create & Drop
Change Database:
>> use <database>
Create Database
Just switch and create an object…
Delete Database
> use mydb;
> db.dropDatabase();

Collections Manipulation
Create Collcation
• > db.createCollection(collectionName)
Delete Collection
• > db.collectionName.drop()
Or just insert to it

INSERT
j = { name : "mongo" }
k = { x : 3 }
db.things.insert( j )
db.things.insert( k )

SELECT: No SQL, just ORM…
Select All
db.things.find()
WHERE
db.posts.find({“comments.email” : ”b@c.com”})
Pattern Matching
db.posts.find( {“title” : /mongo/i} )
Sort
db.posts.find().sort({email : 1, date : -1});
Limit
db.posts.find().limit(3)

Specific fields
Select All
db.users.find(
{ },
{ user_id: 1, status: 1, _id: 0 }
)
1: Show; 0: don’t show
< WHERE
< SELECT user_id, status

WHERE
!= “A” { $ne: "A" }
> 25 { $gt: 25 }
> 25 AND <= 50 { $gt: 25, $lte: 50 }
Like ‘bc%’ /^bc/
< 25 OR >= 50 { $or : [ { $lt: 25 }, { $gte : 50 } ] }

Join
Wrong Place…
Or Map Reduce

GROUP BY
db.article.aggregate(
{ $group : {
_id : { author : "$author“, name : “$name” },
docsPerAuthor : { $sum : 1 },
viewsPerAuthor : { $sum : "$pageViews" }
}}
);
< GROUP BY author, name
< SUM(pageViews)
< SUM(1) = N

UPDATE
db.posts.update(
{“comments.email”: ”b@c.com”},
{$set : {“comments.email”: ”d@c.com”}}
}
SET age = age + 3
db.users.update(
{ status: "A" } ,
{ $inc: { age: 3 } },
{ multi: true }
)

DELETE
db.users.remove(
{ status: "D" }
)

THE MEAN PLATFORM
Introduction
30

http://top-performance.blogspot.com31

The MEAN flow
32
http://scotch.io/tutorials/javascript/creating-a-single-page-todo-app-with-node-and-angular

Node + Express Installation
• yum repolist
• sudo rpm --import https://fedoraproject.org/static/0608B895.txt
• sudo rpm -Uvh http://download-
i2.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
• sudo yum -y install nodejs npm --enablerepo=epel
• sudo yum -y install npm --enablerepo=epel
• sudo npm install -g express
• sudo npm install -g express-generator
33

My First App
• express node_test
• sudo vi package.json
• ,
• "mongodb": "*",
• "monk": "*“
• cp node_test
• npm install
• mkdir data
• npm start
• wget http://localhost:3000/
34

THE A/A CASE STUDY
Introduction
35

DNS based Load Balancing Architecture
36

MIGRATION CONSIDERATIONS
Introduction
37

Data Migration
Map the table structure
Export the data and Import It
Add Indexes
38
http://igcse-geography-lancaster.wikispaces.com/1.2+MIGRATION

Selected Migration Tool
39

Usage Details
> Install ruby
> gem install mongify
… Modify the code to your needs
… Create configuration files
> mongify translation db.config >
translation.rb
> mongify process db.config translation.rb
40

Date Functions
Year(), Month()… function included
… buy only in the JavaScript engine
Solution: New fields!
[original field]
[original field]_[year part]
[original field]_[month part]
[original field]_[day part]
[original field]_[hour part]
41

NO SCHEMA IS A GOOD THING
BUT…
Schemaless
42

Default Values
No Schema
No Default Values
App Challenge
Timestamps…
No single source of truth
43

Casting and Type Safety
No Schema
No …
App Challenge
44

Auto Numbers
Start using _id
{
"_id" : 0,
"health" : 1,
"stateStr" : "PRIMARY",
"uptime" : 59917,
}
Counter tables
Dedicated database
1:1 Mapping
Counter++ using findAndModify
45

The ORM Solution
46

Data Analysts
47
http://www.designersplayground.com/pr/internet-meme-list/data-analyst-2/

Data Analysts
This is not SQL
There are no joins
No perfect tools
48
Pentaho
RockMongoMongoVUE RoboMongo

No Joins
Do in the application
Leverage the power of NoSQL
49

Limited Resultset
50
16MB document size
Limit and Skip
Adjusted WHERE

Bottom Line
Powerful tool
Embrace the Challenge
Schema-less limitations: counters, data types
Tools for Data Scientists
Data design
51

Scale Hacking
Moshe Kaplan 972-54-2291978
moshe.kaplan@brightaqua.com

Introduction to MongoDB

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