Cassandra - Do inferno ao Céu

1. NOSQL
Setup for Java
Developers
Bruno Tinoco
08.07.2016

2. AGENDA
1. Introduction
2. Setup
3. Hands-on experience
4. References

3. GFT Group 03.09.2015 3
Who I am and What I do
INTRODUCTION
GFT Group is a business change and
technology consultancy trusted by
the world’s leading financial services
institutions bringing together advisory,
creative and technology capabilities
with innovation culture and specialist
knowledge of the finance sector.
Bruno Tinoco
 Father and Java Developer with more
than 15 years of software development
experience using the JavaEE platform for
different companies from Financial to
Travel and Distribution industries.
 Currently working as a Software Engineer
at GFT Group for DeustcheBank projects.
Previously I worked as IT Architect at IBM
GBS projects.
 Follow us
 https://twitter.com/gft_br
 https://twitter.com/brunocrt

4. GFT Group 03.09.2015 4
What is the thing about Cassandra
INTRODUCTION
 Distributed Database (CAP)
 Fault tolerant cluster
 Nominated master
 Native JSON
 Distributed hash table (Partition Keys)
 Replication factor
 Tunable consistency (ONE,QUORUM, ALL)
SchemaKeyspace
Column Family Table
~Row Key
(Partition key
Clustering column)
Primary
key
 No JOINS
 No Foreign keys
 No rollback/locking
 Eventual/Tunable Consistence
SQLCQL

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Downloading, Installing, Configuring & Running
SETUP
http://cassandra.apache.org
(Current latest version 3.7)
apache-cassandra-3.7-bin.tar.gz
(34MB)
cassandra.yaml
./bin/cassandra
data
logs
export JAVA_HOME
export MAX_HEAP_SIZE=“1024M”
export HEAP_NEWSIZE=“400M”
Cassandra = v2.2 – Java 7
Cassandra > v3.0 – Java 8

6. GFT Group 03.09.2015 6
Setup your project
HANDS-ON EXPERIENCE
Define your persistence model
Kundera Cassandra Driver
<dependency>
<groupId> com.impetus.kundera.client </groupId>
<artifactId> kundera-cassandra </ artifactId >
<version> 3.4 </version>
</dependency>
Native Queries (CQL)JPA
DataStax Driver *
<dependency>
<groupId> com.datastax.cassandra</groupId>
<artifactId> cassandra-driver-core </ artifactId >
<version> 3.0.0 </version>
</dependency>
* Also supports object mapping through
cassandra-driver-mapping
You can starting mapping your entity classes using
standard JPA annotations…
You must to learn the driver API and
create the schema yourself first
X
Others
Hector
Pelops
Astyanax

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Setup your tools
HANDS-ON EXPERIENCE
 CQLSH
 DataStax DevCenter
 DataStax OpsCenter (Monitoring)

8. GFT Group 03.09.2015 8
How about data modelling
HANDS-ON EXPERIENCE
 Think about sorted Maps
 Data Types (List, Json)
 N-to-N Relationships
SortedMap<RowKey, SortedMap<ColumnKey, ColumnValue>

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Keep in mind
HANDS-ON EXPERIENCE
 First your Use Case (UI needs)
 Do not try to normalize data (Hardest part)
 Define carefully your partition key (Performance)

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More Information...
REFERENCES
Cassandra Community (Forum, Tutorials)
http://www.planetcassandra.org/
Apache Cassandra Home (Download)
https://cassandra.apache.org/
Netflix Cassandra benchmark
http://techblog.netflix.com/2011/11/benchmarking-cassandra-scalability-on.html
DataStax Documentation (Tutorials, Guide, Sample code)
https://docs.datastax.com/

11. Thank you
Bruno.tinoco@gft.com
Senior Software Engineer
GFT Brasil

12. GFT Group 03.09.2015 12
CREATING OBJECTS
 Keyspace
 CREATE KEYSPACE demo WITH replication = { 'class': 'SimpleStrategy', 'replication_factor': '1' };
 Table
 CREATE TABLE users ( firstname text, lastname text, age int, email text, city text, PRIMARY KEY (lastname));
 Queries
 SELECT… / INSERT…
 Indexes
 CREATE INDEX…
 Structure
 DESC…
BASIC COMMANDS

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CQLSH
 Interactive mode (shell)
 $CASSANDRA_HOME/bin/cqlsh localhost –u user –p user123
 clqsh>
 Execute mode
 $CASSANDRA_HOME/bin/cqlsh localhost –u user –p user123 –e “SELECT * from demo.users”
 File mode
 $CASSANDRA_HOME/bin/cqlsh localhost –u user –p user123 –f my_cql_commands.cql
TOOLS
Python script that comes with the default Cassandra a installation

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DataStax DevCenter
 Free tool GUI for connect on Cassandra clusters
TOOLS

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DataStax Driver
 Support both Binary (CQL) and Thrift Protocols
 Connection Pool
 Supports Annotation (Tables/Indexes/Types)
 Supports Native Cassandra concepts
JAVA DRIVERS

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Kundera Driver
 JPA Compliant
 Annotation based
 Auto schema creation
 Connection Pool
 Support other NoSQL databases (ie. Mongo)
JAVA DRIVERS

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Other Drivers
 Hector
The most stable of the Java APIs, ready for prime-time.
 Astyanax
A clean Java API from Netflix. It isn't as widely used as Hector, but it is solid.
 Pelops
 PlayORM (ORM without the constraints?)
It looks like it is trying to solve the impedance mismatch between traditional JPA-based ORMs
and NoSQL by introducing JQL. It looks promising.
Decision Considerations
 Low latency overhead, Asynch API, and reliability/stability for production environment.
(e.g. a more user-friendly APIs that can be had in the DAL that wraps the client).
 Connection pooling and partition awareness are some other good feature to have.
 Able to detect any new nodes that got added.
 Good Support as well (as pointed by dean below)
JAVA DRIVERS