Overview of NewCassandra Drivers

Michaël FiguièreEngineer & Developer Advocate, DataStax@mfiguiere

©2012 DataStax

Past Drivers Architecture

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Thrift API

Thrift RPC

* This is a simplified view of drivers architecture. Details vary from one language to another.

OO API

Client Library

©2012 DataStax

Current Drivers Architecture

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Thrift API

Thrift RPC

CQL API

Thrift RPC

DB API

* This is a simplified view of drivers architecture. Details vary from one language to another.

OO API

Client Library CQL Driver

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CQL: the new face of Cassandra

• CQL 3• Simpler Data Model using denormalized Tables• SQL-like query language• Schema definition

• CQL Binary Protocol• To be introduced in Cassandra 1.2 (CASSANDRA-2478)• Designed for CQL 3• Opens doors for Streaming, Notifications, ...• Thrift will keep being supported by Cassandra

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New Drivers Architecture

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DB API

CQL Native Protocol

CQL API OO API

* This is a simplified view of drivers architecture. Details vary from one language to another.

Next Generation Driver

©2012 DataStax

Request Pipelining

6

Client

WithoutRequest Pipelining

Cassandra

Client CassandraWith

Request Pipelining

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Notifications

7

Client

WithoutNotifications

WithNotifications

NodeNode

Node

Client

NodeNode

Node

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Java Driver• Reference Implementation

• Asynchronous architecture based on Netty

• Prepared Statements Support

• Automatic Fail-over

• Node Discovery

• Cassandra Tracing Support

• Tunable policies• LoadBalancingPolicy• ReconnectionPolicy• RetryPolicy

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Connect and Write

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Cluster cluster = new Cluster.Builder() .addContactPoints("127.0.0.1", "127.0.0.2") .build();

Session session = cluster.connect();

session.execute( "INSERT INTO user (user_id, name, email) VALUES (12345, 'johndoe', 'john@doe.com')");

©2012 DataStax

Read

10

ResultSet rs = session.execute("SELECT * FROM test");

List<CQLRow> rows = rs.fetchAll(); for (CQLRow row : rows) {

String userId = row.getString("user_id"); String name = row.getString("name"); String email = row.getString("email");}

©2012 DataStax

Asynchronous Read

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ResultSet.Future future = session.executeAsync("SELECT * FROM test");

ResultSet rs = future.get();

List<CQLRow> rows = rs.fetchAll(); for (CQLRow row : rows) {

String userId = row.getString("user_id"); String name = row.getString("name"); String email = row.getString("email");}

©2012 DataStax

Mapping in Java

• JPA• Standard and very popular API• Very relational oriented• Hard for developers to figure out which part is usable

• JPA-ish• A mapping API designed for Cassandra• Most annotations borrowed and modified from JPA• Get rid of non relevant components• Add some Cassandra-specific concepts

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Object Mapping

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public enum Gender {

@EnumValue("m") MALE, @EnumValue("f") FEMALE;}

@Table("user_and_messages")public class User { @Column("user_id") private String userId; private String name; private String email; private Gender gender;}

©2012 DataStax

Sample Data Model

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user_and_messages Table

CREATE TABLE user_and_messages ( user_id varchar, msg_id int, title varchar, body varchar, PRIMARY KEY (user_id, msg_id));

CQL

gmason

user_id

Hello!

title

Give me liberty or give me death

body

gmason Bonjour ! I chopped down the cherry tree

ahamilton Hallo ! A government of laws, not men

ahamilton ¡Hola I chopped down the cherry tree

msg_id

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7

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Aggregation

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@Table("user_and_messages")public class User { @Column("user_id") private String userId; @GroupBy("user_id") private List<Message> messages;}

public class Message {

private String title; private String body; }

gmason

user_id

Hello!

title

Give me liberty or give me death

body

gmason Bonjour ! I chopped down the cherry tree

ahamilton Hallo ! A government of laws, not men

ahamilton ¡Hola I chopped down the cherry tree

msg_id

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©2012 DataStax

Inheritance

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@InheritanceValue("tv")public class TV extends Product {

private float size;}

@Table("catalog")@Inheritance({Phone.class, TV.class})@InheritanceColumn("product_type")public abstract class Product {

@Column("product_id") private String productId; private float price; private String vendor; private String model;

}

https://github.com/datastax/java-driver

Now Available!

@mfiguiere

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Stay Tuned!