Setting Up Cassandra for Development

Let's get a local Cluster

• Cassandra Cluster Manager (CCM)
• https://github.com/pcmanus/ccm
• Works with Cassandra and DataStax Enterprise
• Quickly setup/tear down clusters for development

ccm create cassandra_dev_cluster -n 3 -v 2.1.2

ccm create dse_dev_cluster --dse 
  --dse-username=philip.s.doctor_gmail.com 
  --dse-password=ffddHgn5rS -v 4.6.5


ccm start

Cqlsh

• CQL is Cassandra Query Language, it looks a lot like SQL
• There is a shell for connecting to a node and trying out commands, let's try it.

./ccm status
Cluster: 'cassandra_dev_cluster'
--------------------------------
node1: UP
node3: UP
node2: UP

./ccm node2 cqlsh
Connected to cassandra_dev_cluster 
at 127.0.0.2:9042.

Create a Keyspace

• Keyspaces manage tables
• They specify Replication Factor (RF)
• They specify Replication Strategy (where data goes)
• SimpleStrategy is a Replication Strategy that says "Store on node that partitioner says, then go around the ring clockwise for replicas"

CREATE KEYSPACE intro
  WITH REPLICATION = 
{ 'class' : 'SimpleStrategy', 
  'replication_factor' : 3 };

use intro;

Create a Table

• Tables hold your data
• Choose a Primary Key that fits your data usage patterns.
• Specify other options such as encryption and compression.
• Lots of table creation options useful for optimizations.

CREATE TABLE test_data (
  data_id int PRIMARY KEY,
  data_item text
);

Insert and Select Data

• When selecting, we don't have joins and we want to select using the primary key if we can.

insert into test_data (data_id, data_item) 
values (1, 'foo');

select * from test_data where data_id = 1;

Replication Power

• One last demo, let's see some nodes "crash" on us and what it looks like to a client consuming Cassandra.

ccm node1 stop && ccm node2 stop
ccm status
ccm node3 cqlsh

Learn More

Datastax Academy

https://academy.datastax.com/

Datastax Documentation

http://docs.datastax.com/en/cql/3.1/cql/cql_reference/create_keyspace_r.html

http://docs.datastax.com/en/cql/3.1/cql/cql_reference/create_table_r.html

CCM

https://github.com/pcmanus/ccm