NoSQL database Cassandra was created at Facebook in 2007, uses a decentralized peer-to-peer architecture for high availability and scalability. It is influenced by BigTable for its column family data model and Dynamo for its high availability and eventual consistency. Cassandra uses a flexible data model of keyspaces, column families, and columns and supports tunable consistency levels for reads and writes.

1. A Quick Look At
Bryan Williams

2. No SQL

3. History
Created at Facebook in 2007
Open Sourced in 2008
Currently version 0.6.6
Version 0.7 in Beta 3

4. CAP Theorem
Consistency
Availability
Partition Tolerance

7. Scaling
Vertical
More RAM
Faster CPU
Faster HD
Horizontal
More Servers
Shared Load

8. Features
Decentralized (peer to peer)
Elastic
Shared Nothing Architecture
Tuneable Consistency
Always Writeable
Optimized for excellent throughput on
writes

9. Influences
BigTable
column family data model
High Throughput Writes
Dynamo
Hight availabilty
Scalability
Eventual Consistency (Tuneable)

10. Data Model
Cluster
Keyspace
Column Families
Super Columns
Columns

14. Cassandra’s CLI
(Command Line Interface)

15. Secondary Indexes
Use another column family with reverse
lookup
Specify Metadata on the Column Family
and set the index name and type
Support coming in 0.7

16. Writes
Commit Logs
Memtable
SSTable
Hinted Handoff
Bloom Filter
Tombstone

17. Partitioning
Random Partitioner
Order Preserving Partitioner
Collating Order Preserving Partitioner
Byte Order Partitioner

18. Snitches
Simple Snitch
Property File Snitch

19. Column Sorting
AsciiType
BytesType
LexicalUUIDType
LongType
IntegerType
TimeUUIDType
UTF8Type
Custom

20. Replication Factor
Set per keyspace
Specified in servers config file
Indicates how many nodes you want to
store a value in on every write

21. Consistency Level
Set per query
Specified by the client
Indicates how many nodes the client has
decided must respond for a successful
read/write
Based on replication factor, not on the
number of nodes in the system

22. Write Consistency
Levels
Zero: No response required
Any: 1st response from any node
One: 1st response (counting Hints)
quorum: n/2 + 1
All: All replicas must respond

23. Read Consistency
Levels
One: The first response is taken
Quorum: N/2 + 1 replicas are required
to respond
All: All replicas are required to
respond

24. Gossiper
Protocol used for intra-ring
communication
Runs every second on a timer
Used by hinted-handoff

25. Anti-Entropy
Replica synchronization mechanism
Ensures data on different nodes are up
to date
merkle trees
Happens after each update

26. Read Repair
When a read operation found
inconsistent data in different nodes
Timestamp for all replicas are checked
all replicas are updated based on most
recent value
Weak vs Strong consistency entails
whether Read Repair happens before or
after returning results

27. Replication
Strategies
Simple Strategy
Old Network Topology Strategy
Network Topology Strategy

28. Java Client
Options
Thrift : http://incubator.apache.org/thrift
Avro : http://avro.apache.org
Hector : https://github.com/rantav/hector
Pelops : http://code.google.com/p/pelops
Kundera : http://code.google.com/p/kundera
More : http://wiki.apache.org/cassandra/ClientOptions

29. Cassandra: The Definitive Guide
Author:
Eben
Hewitt
Publisher:
Oreilly
Release:
Late
November

30. Thanks For Coming
Bryan Williams
Email : Bwilliams@integrallis.com
Twitter : @BryWilliams
LINKS
http://cassandra.apache.org
http://wiki.apache.org
https://github.com/ericflo/twissandra