Apache Cassandra Learning Step by Step (1)

By Bright Zheng (IT进行时)

1.   About Apache Cassandra

Apache Cassandra is one of the powerful NoSQL platforms.

Link: http://cassandra.apache.org/

 

Following are some useful comparisons on some classic NoSQL platforms which we need to make a decision if we want to get involved in such a domain.

      1. Cassandra vs MongoDB vs CouchDB vs Redis vs Riak vs HBase vs Membase vs Neo4j comparison: http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis

      2. HBase vs Cassandra: http://blog.adku.com/2011/02/hbase-vs-cassandra.html

2.  Development environment Setup

2.1.  Software required

SN	Name	Description
1	Apache Cansandra	Mandatory. Current stable version is 1.0.7 @http://cassandra.apache.org/download/
2	Cassandra Tutorial	Mandatory. Source code for following writeups. @http://github.com/zznate/cassandra-tutorial.git
3	GIT	Optional. Tools for latest source code download & sync
4	Maven	Optional. I’m using 3.x, or 3.0.3 exactly.
5	Hactor	Optional. Recommended Java client implementation for deeper learning experience since it encapsulates all Cassandra’s Concepts/APIs as a higer layer Concepts/APIs.

2.2. Software install & configuration

2.2.1. Apache Cassandra (as single node first)

Download & unzip, that’s almost done.

Better to configure two files for some runtime info (data/log/etc.).

 

1. $APACHE_CASSANDRA$/conf/cassandra.yaml

cluster_name: 'Test Cluster'

 

# directories where Cassandra should store data on disk.

data_file_directories:

    - ../runtime/data

 

# commit log

commitlog_directory: ../runtime/commitlog

 

# saved caches

saved_caches_directory: ../runtime/saved_caches

 

2. $APACHE_CASSANDRA$/conf/log4j-server.properties

log4j.appender.R.File=../runtime/system.log

 

Double click $APACHE_CASSANDRA$/bin/cassandra.bat  to start Cassandra.

 

If you want to enable JMX for runtime monitoring, please download MX4J from here and extract mx4j.jar and mx4j-tools.jar to $APACHE_CASSANDRA$/lib and then restart Cassandra.

One more thing you should understand is that the JMX port will be defaulted to 8081 (Ref to the source code here). If you got port conflict issue, you have two ways to change the port.

1. Add a parameter to the start up bat (or $APACHE_CASSANDRA$/bin/cassandra.bat) as -Dmx4jport=8082, or

2. Change the bat directly at following lines:
@REM original
@REM "%JAVA_HOME%\bin\java" %JAVA_OPTS% %CASSANDRA_PARAMS% -cp %CASSANDRA_CLASSPATH% "%CASSANDRA_MAIN%"
@REM change to follwing
set mx4jport=7599
"%JAVA_HOME%\bin\java" %JAVA_OPTS% %CASSANDRA_PARAMS% -Dmx4jport=%mx4jport% -cp %CASSANDRA_CLASSPATH% "%CASSANDRA_MAIN%"

2.2.2. Git & Maven

Omitted…

2.2.3.  Cassandra Tutorial

1. Open Git Bash:

By double clicking the Git Bash under Git install folder.

 

2. Download the source:

git clone http://github.com/zznate/cassandra-tutorial.git

Note:

If your network is via proxy, run follwing command first:

export http_proxy={YOUR PROXY HOST/IP}:{PORT}

 

3. Import to Eclipse:

This is a maven project so we can import it to Eclipse as existing Maven project.

2.2.4. Hactor

1. Open Git Bash:

By double clicking the Git Bash under Git install folder.

 

2. Download the source:

git clone http://github.com/rantav/hector.git

 

3. Import to Eclipse:

Hactor is a mavan project(s). So we can import it to Eclipse as existing maven project.

It has 3 sub projects: core, orm & test.

 

Take note that the orm sub project is lack of javax.persistence dependency.

I added it as org.hibernate.javax.persistence: hibernate-jpa-2.0-api.jar

TODO Items:

3. Samples Step by Step: By combining Concept Intro, CLI Usage & Sample Java Code

4. Clustering & Tuning: To evaluate Cassandra so-called Linear Scalability and proven Fault-tolerance