NOSQL Session GlueCon May 2010

NoSQL : Channeling the Data Explosion
Dwight MerrimanCEO, 10gen
@dmerr dmerr.tumblr.com
GlueCon 2010

The database world is changingNo longer one-size-fits-all

NoSQL =
Non-relational next generation operation data stores and databases

Scaling Out
no joins +
light transactional semantics =
horizontally scalable architectures

Why?
cloud
commodity
http://www.globalnerdy.com/2007/09/07/multicore-musings/

How the NoSQL Products Vary
What’s the same
No joins
No complex transactions
What varies
Scale-out model
Consistency model
Data model

Scaling Out
distribution & query models
Consistent hashing
Order preserving range
chunking
Scatter gather

Data models
no joins +
light transactional semantics =
horizontally scalable architectures
Important side effect :
new data models =
improved ways to develop apps

Data Models
Key/value
Column-oriented “bigtable-style”
Document-oriented (JSON)

Data Models
{ title: ‘Too Big to Fail’,
author: ‘John S’,
ts: Date(“05-Nov-09 10:33”),
comments: [ { author: 'Ian White',
comment: 'Great article!' },
{ author: 'Joe Smith',
comment: 'But how fast is it?',
replies: [ {author: 'Jane Smith',
comment: 'scalable?'} ]
}
]
],
tags: [‘finance’, ‘economy’]
}

{ title: ‘Too Big to Fail’,
author: ‘John S’,
ts: Date(“05-Nov-09 10:33”),
comments: [ { author: 'Ian White',
comment: 'Great article!' },
{ author: 'Joe Smith',
comment: 'But how fast is it?',
replies: [ {author: 'Jane Smith',
comment: 'scalable?'} ]
}
]
],
tags: [‘finance’, ‘economy’]
}
db.posts.find( { tags : ‘economy’ } )
.sort({ts:-1}).limit(10).skip(10)
db.posts.find( { “comments.author” : “Ian White” } )

Influences

CAP
It is impossible in the asynchronous network model to implement a read/write data object that guarantees the following properties:• Availability• Atomic consistency in all fair executions (including those in which messages are lost).

Consistency Models - CAP
Choices are AP or CP
Write Availability, not Read Availability, is the Main Question
It’s not all about CAP
Eventual consistency makes these non-availability aspects better:
Multi data center
Speed
Even load distribution

Eventual Consistency

Eventual Consistency
Read(x) : 1, 2, 2, 4, 4, 4, 4 …

Could we get this?
Read(x) : 1, 2, 1, 4, 2, 4, 4, 4 …

Terms
R
W
N
R+W>N has nice properties
Sloppy quorum

R+W>N
If R+W > N, we can’t have both fast local reads and writes at the same time if all the data centers are equal peers?

Network Partitions

Trivial Network Partitions

Sometimes we need global state / more consistency
Unique key constraints
User registration
ACL changes
Are we surprising the user?
read-your-own-writes

Could it be the case that…
uptime( CP + average developer )
>=
uptime( AP + average developer )
where uptime:= system is up and non-buggy?

Predictions
JSON will be the most popular building block for non-relational data models
Tunable consistency in all the products
Some SQL in these products!

Questions?Thank you
dwight@10gen.com
@dmerr
dmerr.tumblr.com
@mongodb
Download : www.mongodb.org
10gen is hiring in SF and NYC – info@10gen.com

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NOSQL Session GlueCon May 2010

by Dwight Merriman on May 26, 2010

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NOSQL Session GlueCon May 2010 — Presentation Transcript