1) The document discusses Cassandra tools including the DataStax CQL drivers and the new DevCenter visual query tool. 2) The CQL drivers provide an asynchronous architecture based on Netty, support prepared statements, automatic failover, and tunable policies. 3) DevCenter is a free visual query tool that can be used by developers and admins for creating and running CQL queries and commands against Apache Cassandra and DataStax Enterprise. It is intended to be a smarter and friendlier alternative to cqlsh.

1. #CASSANDRAEU
Cassandra made simple
with CQL drivers and DevCenter
Michaël Figuiere, Software Engineer, DataStax
!
Alex Popescu, Sen.Product Manager, DataStax

2. Agenda
•Why building tools for Cassandra?
•DataStax Drivers
• Core values
•Introducing DevCenter
#CASSANDRAEU

3. Motivation
«Use the right tool for the job»
... the best tools for the job
#CASSANDRAEU

4. Why building tools for C*
•Too many choices
•Best practices
•distributed systems
•modern applications
•Friendly, Familiar, Integrated experience
#CASSANDRAEU

5. One way or another
•Learn & experiment
•Implement
•Test
•Integrate
!
•Repeat
#CASSANDRAEU

6. CQL The new face of Cassandra
* CQL
* Simpler Data Model using Denormalized Tables
* SQL-like Query Language
* Schema Definition
* CQL Native Protocol
* Introduced in Cassandra 1.2
* Designed for CQL
* Thrift will keep being supported by Cassandra

7. CQL Drivers Overview
* Reference Implementation
* Asynchronous architecture based on Netty
* Prepared Statements Support
* Automatic Fail-over
* Node Discovery
* Cassandra Tracing Support
* Tunable Policies
!

8. Request Pipelining
Client
Cassandra
Without
Request
Pipelining
Client
Cassandra
With
Request
Pipelining

9. Notifications
Node
Client
Node
Node
With
Notifications
Node
Client
Node
Without
Notifications
Node

10. Asynchronous Architecture
Nod
Client
Thread
Nod
Client
Thread
Driver
Nod
Client
Thread
Nod

11. Asynchronous Architecture
Nod
Client
Thread
6
Nod
1
Client
Thread
2
Driver
3
Nod
5
Client
Thread
4
Nod

12. Connect and Write
Cluster cluster = new Cluster.builder()
.addContactPoints("10.0.0.1", "10.0.0.2")
.build();
!
Session session = cluster.connect("myKeyspace");
!
session.execute(
"INSERT INTO user (user_id, name, email)
VALUES (12345, 'johndoe', 'john@doe.com')"
);

13. Read from a table
ResultSet rs = session.execute("SELECT * FROM test");
!
List<Row> rows = rs.all();
for (Row row : rows) {
!
String userId = row.getString("user_id");
String name = row.getString("name");
String email = row.getString("email");
}

14. Asynchronous Read
ResultSetFuture future =
session.executeAsync("SELECT * FROM test");
!
for (Row row : future.get()) {
!
String userId = row.getString("user_id");
String name = row.getString("name");
String email = row.getString("email");
}

15. Read with Callbacks
final ResultSetFuture future =
session.executeAsync("SELECT * FROM test");
!
future.addListener(new Runnable() {
public run() {
for (Row row : future.get()) {
!
String userId = row.getString("user_id");
String name = row.getString("name");
String email = row.getString("email");
}
}
}, executor);

16. Using Prepared Statements
public void setUserByPreparedStatement(User user) {!
!
BoundStatement bs = setUser.bind();!
!
bs.setString("username", user.getUsername());!
bs.setString("firstname", user.getFirstname());!
bs.setString("lastname", user.getLastname());!
bs.setString("email", user.getEmail());!
bs.setDate("created_date", user.getCreated_date());!
!
!
!
session.execute(bs); !
}

17. Using the Query Builder
Query query = select().all().from("videodb", "videos")!
.where(eq("videoId", videoId)).limit(10);!
!
query.setConsistencyLevel(ConsistencyLevel.ONE);!
!
ResultSet rs = session.execute(query);!

18. Load Balancing and Failover
Respons
e
5
Retry
Policy
4
6
Client
1
Load
Balancing
Policy
3
Node
Node
2
Node
Health
Monitor
Notifications
Reconnection

19. Multi Datacenter Load Balancing
Datacenter A
Client
Node
Client
Node
Client
Node
Client
Node
Client
Client
Node
Node
Datacenter B
Local nodes are
queried first, if non
are available, the
request will be
sent to a remote
node.

20. Token Aware Load Balancing
Replic
Node
a
Node
Replic
Node
Client
a
Node
Replic
a
Node
Nodes that own
a Replica of the
data being read
or written by the
query will be
contacted first.

21. Add a Load Balancing Policy
!
!
cluster = Cluster.builder()!
.addContactPoints("10.0.0.1", "10.0.0.2")
.withLoadBalancingPolicy(Policies.defaultLoadBalancingPolicy())!
.build();!
!
session = cluster.connect(keyspace);!
Create your own policy!

22. Automatic Paging
Nod
Query
Client
Page 1
+ Paging State 1
Repli
Nod
Repli
Nod
Repli

23. Automatic Paging
Nod
Repli
Query + Paging State 1
Client
Nod
Repli
Page 2 + Paging State 2
Nod
Repli

24. Introducing DevCenter 1.0

25. DevCenter
#CASSANDRAEU
•DevCenter is a free visual query tool that can be used by
both developers and admins for creating and running
CQL queries and commands against Apache Cassandra
and DataStax Enterprise
•DevCenter is the
smarter and friendlier
brother of cqlsh

26. DevCenter
#CASSANDRAEU
Pull a Steve Jobs...
... brag about how
brilliant DevCenter is

27. #CASSANDRAEU
Quick links
*DataStax drivers:
http://github.com/datastax
*DevCenter:
http://www.datastax.com/dev/blog/datastaxdevcenter-1-0-is-here
http://www.datastax.com/download/clientdrivers
!