CassandraA highly scalable, eventually consistent, distributed, structured key-value store.

The cursedoracle of Troy.

StructuredKey-Value Store

Berkely DB, Memcached, etc

Name Value

Super Column

Cassandra

Super ColumnName

Column

Name Value

Distributed

Node 1

Node 2

Node 3

Node 4

Node 5

Node 6

Eventually Consistent

Node 1

Node 2

Node 3

Node 4

Write

Node 1

Node 2

Node 3

Node 4

Read

Write

Node 1

Node 2

Node 3

Node 4

Highly Scalable

Node 4

Node 5

Node 6

Node 1

Node 2

Node 3

Node 4

Node 5

Node 6

Node 1Node 2

Node 3

Node 3.5

Fault Tolerant

Node 1

Node 2

Node 3

Node 4

Node 5

Node 6

Node 1

Node 2

Node 3

Node 4

Node 5

Node 6

Rich Data Model

// Column:{ emailAddress: ‘jill@example.com’ }

// Super Column:homeAddress: { // Columns: street: ‘1234 Example St.’, city: ‘Santa Cruz’, state: ‘CA’, zip: ‘91210’}

// Column Family:userProfiles: { // Rows: bob2007: { // Columns: username: ‘bob2007’, age: 32, phone: ‘(818) 555-2345’ }, birdHOUSE: { username: ‘birdHOUSE’, name: ‘George’, age: 19 }}

// Super Column Family:addressBook: { // Rows: bob2007: { // Super Columns: Joe: { email:’joe@example.com’ }, Ted: { street:’123 Jump St.’, phone:’555-1234’ } } birdHOUSE: { mom: { birthday:’1953-03-07’, phone:’555-7894’ } }}

Time for an example.Any questions?