慕课网 《MongoDB 2014北京大会》视频笔记

学习地址：MongoDB 2014北京大会

第一章 MongoDB欢迎致辞及MongoDB简介

General purpose

Document database

Open-source

Create Applications — Never Before Possible



MongoDB Business Value:

- Enabiling New Apps

- BetterCustomer Experience

- Faster Time to Marker

- Lower TCO

What we sell?

MongoDB Enterprise Advanced

Management platform, advanced security, proactive support, and more.

MongoDB Management Service(MMS)

Automated deployment, upgrades, backup and monitoring in the cloud.

Production Support

Support for production deployments.

Development Support

Support, on-demand training and health check for teams in development.

Consulting

Packaged service offerings for critical points in the project lifecycle.

Training

Certification and training in development and ops - online & in-person.

THE LARGEST ECOSYSTEM

- 9,000,000+

MongoDB Downloads

- 250,000+

Online Education Registrants

- 35,000+

MongoDB User Group Members

- 40,000+

MongoDB Management Service(MMS) Users

- 600+

Technology and Services Partners

- 1,000+

Custormers Across All Industries

Document Level Locking

( Coming early 2015 )

pluggable : In-memory, RocksDB, TokuKV, FusionIO

What is the storage engine today?

MMAP & WiredTiger

Automation

第2章 MongoDB模式设计的艺术：该做的与不该做的

The Fine Art of Schema Design: Dos and Don’ts

(Matias Cas callares

Senior Solutions Architect, MongoB Inc.

matias@mongodb.com)

RDBMs

Relational databases are made up of tables

Tables are made up of rows:

All rows have identical structure

Each row has the same number of columns

Every cell in a column stores the same type of data

MongoDB is a Document Oriented database

Document Model

MongoDB is made up of collections

Collections are composed of documents

Each document is a set of key-value pairs

No predefined schema

Keys are always strings

Values can be any(supported) data type

Values can also be an array

Values can also be a document

document inside documents

Benifits of these document model….?

Flexibility

Each document can have different fields

No need of long migrations, easier to be agile

Common structure enforced at application level

Arrays

Documents can have field with array values

Ability to query and index array elements

We can model relationships with no need of different tables or collections

Embedded documents

Documents can have field with document values

Ability to query and index nested documents

Semantic closer to Object Oriented Programming

Relational Schema Design:

Focus on data storage.

Document Schema Design:

Focus on data usage.

SCHEMA DESIGN IS AN ART

A task tracking app

Requirement #1

“We need to store user information” like name, email and their addresses…yes they can have mort than one.”

—Bill, a project manager, contemporary

Requirement #2

“We have to be able to store tasks, assign them to users and track their progress…”

—Bill, a project manager, contemporary

Embedding tasks

Tasks are unbounded items: initially we do not know how many tasks we are going to have

A user along time can end with thousands of tasks

Maximum document size in MongoDB: 16MB!

It is harder to access task information without a user context

Array update operators

pop

push

pull

pullAll

Why is expensive to move a document?

We need to write the document in another locaion($$)

We need to mark the original position as free for new documents($)

We need to update all those index entries pointing to the moved document to the new location($$$)

Considerations with arrays

Limited number of items

Avoid document movements

Document movements can be delayed with padding factor

Document movement can be mitigated with preallocation

RECIPE #4

USE DATA MODELS THAT MINIMIZE THE NEED FOR DOCUMENT GROWTH

RECIPE #5

DENORMALIZE TO AVOID APP-LEVEL JOINS

RECIPI #6

DENORMALIZE ONLY WHEN YOU HAVE A HIGH READ TO WRITE RATIO

Bucketing

What’s th idea?

Reduce number of documents to be retrieved

Less documents to retrieve mean less disk seeks

Using arrays we can store more than one entity per document

We group things that are accessed together