Lab 4: Interfacing with Cassandra

4: Interfacing with Cassandra

Zubair Nabi

[email protected]

April 20, 2013

Zubair Nabi 4: Interfacing with Cassandra April 20, 2013 1 / 16

Introduction1

Project website: http://cassandra.apache.org/

Column based key value store (multi-level dictionary)Consists of keyspaces and column families

I Keyspace: Namespace for column families (typically one perapplication)

I Column family: Contains multiple columns, each of which has a name,value, and timestamp, and which are referenced by row keys

1Disclaimer: Based on the wonderful talk given by Jeremiah Jordan at PyCon 2012Zubair Nabi 4: Interfacing with Cassandra April 20, 2013 2 / 16

http://cassandra.apache.org/

Introduction1


Column based key value store (multi-level dictionary)

Consists of keyspaces and column familiesI Keyspace: Namespace for column families (typically one per

application)I Column family: Contains multiple columns, each of which has a name,

value, and timestamp, and which are referenced by row keys



Introduction1







Introduction1







Introduction1









Starting up

Running it: sudo cassandra -f

Running the CLI: cassandra-cli


Starting up

Running it: sudo cassandra -f

Running the CLI: cassandra-cli


Creating a keyspace

Connecting to the store: connect localhost/9160;

Creating a keyspace: create keyspace ApplicationDatawith placement_strategy =’org.apache.cassandra.locator.SimpleStrategy’and strategy_options =[{replication_factor:1}];


Creating a keyspace

Connecting to the store: connect localhost/9160;

Creating a keyspace: create keyspace ApplicationDatawith placement_strategy =’org.apache.cassandra.locator.SimpleStrategy’and strategy_options =[{replication_factor:1}];


Creating a column family

Referencing a keyspace: use ApplicationData;

Creating a column family: create column family UserInfoand comparator = ’AsciiType’;


Creating a column family

Referencing a keyspace: use ApplicationData;

Creating a column family: create column family UserInfoand comparator = ’AsciiType’;


Interfacing with Cassandra in Python

Package: pycassa

Webpage: https://github.com/pycassa/pycassa


Interfacing with Cassandra in Python

Package: pycassa

Webpage: https://github.com/pycassa/pycassa


Pycassa Basics

1 import pycassa2 from pycassa.pool import ConnectionPool3 from pycassa.columnfamily import ColumnFamily45 pool = ConnectionPool(’ApplicationData’,

6 [’localhost:9160’])

7 col_fam = ColumnFamily(pool, ’UserInfo’)

8 col_fam.insert(’John’, {’email’: ’[email protected]’})


Read

1 readData = col_fam.get(’John’,

2 columns=[’email’])


Delete

1 col_fam.remove(’John’,

2 columns=[’email’])


Batch

1 col_fam.batch_insert(

2 {’John’: {’email’: ’[email protected]’,

3 ’state’: ’IL’,

4 ’gender’: ’M’},

5 ’Jane’: {’email’: ’[email protected]’,

6 ’state’: ’CA’

7 ’gender’: ’M’}})


Batch Stream

1 b = col_fam.batch(queue_size=10)

23 b.insert(’John’,

4 {’email’: ’[email protected]’,

5 ’state’: ’IL’,

6 ’gender’: ’M’})

78 b.insert(’Jane’,

9 {’email’: ’[email protected]’,

10 ’state’: ’CA’})

1112 b.remove(’John’, [’gender’])

13 b.remove(’Jane’)

14 b.send()


Batch Read

1 readData = col_fam.multiget([’John’, ’Jane’, ’Bill’])


Column Slice

1 d = col_fam.get(’Jane’,

2 column_start=’email’,

3 column_finish=’state’)


Reference(s)

Apache Cassandra and Python:https://pycon-2012-notes.readthedocs.org/en/latest/apache_cassandra_and_python.html


https://pycon-2012-notes.readthedocs.org/en/latest/apache_cassandra_and_python.html

https://pycon-2012-notes.readthedocs.org/en/latest/apache_cassandra_and_python.html

Technology

Lab 4: Interfacing with Cassandra