Amazon SimpleDB
A quick intro
Paolo Negri
twitter @hungryblank

DB

DB?
•SimpleDB
•CouchDB
•MongoDB

DB?
http://www.flickr.com/photos/zheem/3091325244/

Key Value store?
http://www.flickr.com/photos/wdwbarber/1338954161/

A bit like...
• BigTable
• HyperTable
• Redis
• TokyoCabinet
• ...

Different Shades
DB >
KV > http://www.flickr.com/photos/dey/11717609/

Commonalities
Schema less
N O
Just store your data

Commonalities
• No transactions
• No relations
• No datatypes (some)

0.7 seconds to store 1 million records
Fast (TokyoCabinet)
http://www.flickr.com/photos/donsolo/1405885541/

Big datasets
SimpleDB 1.000.000.000
attributes/domain * 100 domains
http://www.flickr.com/photos/digitalart/2101765353/

Key Value
A D H1 A6 < Key
data
data
data
data
< Value

SimpleDB
A
T W
< Key
data
data
}
Attribute >
Attribute value > < Value

SimpleDB
Nested hash of strings

SimpleDB
• Only strings
• No schema (no attribute declaration)
• up to 256 attributes per item
• EVERYTHING INDEXED

SimpleDB
<
Key
Attribute > W
Attribute value >
• 1024 K max length
• Any UT8 character that is
valid in XML docs can be
used

SimpleDB
• 1.000.000.000 attributes per domain
• 100 domains per account
• you can have more than one account

SimpleDB
<wtf>wtf</wtf>
SOAP protocol
http://www.flickr.com/photos/rescuedog/2242215507

SimpleDB
Or “REST”
http://sdb.amazonaws.com/?
AWSAccessKeyId=BLAHBLAH&Action=PutAttributes&Attribute.
0.Name=code&Attribute.
0.Value=31&DomainName=test_domain&ItemName=bar41&Sign
atureMethod=HmacSHA256&SignatureVersion=2&Timestamp=20
09-06-07T23%3A15%3A50Z&Version=2007-11-07&Signature=...

SimpleDB
request
REST or XML
SimpleDB Host
response
XML

SimpleDB Requests
• create/delete domain
• put/get/delete (selectively) attributes
• and... SELECT

SimpleDB
Domain: a container of
(nested) key value
• Up to 10GB big
• Up to 1.000.000.000 attributes stored

SimpleDB - PUT

SimpleDB - GET
you pay bandwidth :)

Oh yes, $$
• first GB data IN free, 0.10$ after
• first GB data OUT free, 0.17$ or less after
• first GB stored is free, 0.25GB/month after

So, PUT again
+
=

Attribute values are always arrays
< Key
}
Attribute >
< Value
Array
Attribute value >
Even if there’s only one value!!

Select
• Sort
• Multiple conditions
• Understands only strings!
• So you need to think when you store your
data

Gems
• hungryblank-aws_sdb_bare (github)
very low level one to one mapping with
SimpleDB calls
• right_aws high level, active recordish api
and an hash api
• aws-sdb not any more mantained but still
working

SimpleDB - Cons
• Eventual Consistency - Data is not
immediately propagated across all nodes…
the latency is usually around a second
• Latency specially if you’re not on ec2
• Protocol - if compared with json stores
• Only strings, lexicographical string only

SimpleDB - Pros
• Is basically free to try out
• Everything is indexed
• Distributed
• Replicated
• Completely hosted on Amazon system

Q?
Paolo Negri
twitter @hungryblank