Using Spark to Process Data From Cassandra for Analytics

After my presentation about Apache Cassandra, most people asked if they can run analytical queries on Cassandra, and how they can integrate Spark with Cassandra. So I decided to write a blog post to demonstrate how we can process data from Cassandra using Spark. In this blog post, I’ll show how I can build a testing environment on Oracle Cloud (Spark + Cassandra), load sample data to Cassandra, and query the data using Spark.

Let me first create an Oracle Big Data Cloud instance. Instead of installing Spark manually, I’ll use Big Data Cloud service so I’ll have both Spark and Zeppelin. Zeppelin is a web-based notebook for interactive data analytics. I’ll use Zeppelin to run Spark scripts and queries.

I login to Oracle Cloud, and start creating Big Data Cloud service. I select “Basic” for deployment profile, because I do not need HIVE, I want only one node (for testing), and I select 2.1 of Spark version. After the service is created, I go to “Access rules” and enable ora_p2bdcsce_ssh because I will need connect to my server through SSH.…

Build a Cassandra Cluster on Docker

In this blog post, I’ll show how we can build a three-node cassandra cluster on Docker for testing. I’ll use official cassandra images instead of creating my own images, so all process will take only a few minutes (depending on your network connection). I assume that you have Docker installed on your PC, have internet connection (I was born in 1976 so it’s normal for me to ask this kind of questions) and your PC has at least 8 GB RAM. First of all, we need to assign about 5 GB RAM to Docker (in case it has less RAM assigned), because each node will require 1.5+ GB RAM to work properly.

Open the docker preferences, click the advanced tab, set the memory to 5 GB or more, and click “apply and restart” docker service. Launch a terminal window, run “docker pull cassandra” command to fetch the latest official cassandra image.…

Introduction to Apache Cassandra

On Friday, I gave a presentation about Apache Cassandra at Big Talk event organized by Komtaş Information Management company. Cassandra is a top level Apache project which is born at Facebook. It is a distributed database for managing large amounts of structured data. It provides highly available service and no single point of failure, even running on commodity harware.

In my previous company, we used Cassandra to store our social platform data. It performs well on even medium-size instances running on Amazon Cloud, so our development team wanted to use it on more projects. I managed both production and test environments, and I can say that it is easy to operate as long as you understand the Cassandra internals. So in this event, I wanted give some introductory information about Apache Cassandra.

By the way, I have to say that audience was great. The room was full. People asked lots of questions during the session, took photos of slides, and gave great feedback. I would like to thank people who joined my session, and Komtaş for organizing the event.…

Using Spark to join data from CSV and MySQL Table

Yesterday, I explained how we can access MySQL database from Zeppelin which comes with Oracle Big Data Cloud Service Compute Edition (BDCSCE). Although we can use Zeppelin to access MySQL, we still need something more powerful to combine data from two different sources (for example data from CSV file and RDBMS tables). Spark is a great choice to process data. In this blog post, I’ll write a simple PySpark (Python for Spark) code which will read from MySQL and CSV, join data and write the output to MySQL again. Please keep in mind that I use Oracle BDCSCE which supports Spark 2.1. So I tested my codes on only Spark 2.1 and used Zeppelin environment. I expect you run all these steps on same environment. Otherwise, you may need to modify paths and codes.

For my sample script, I’ll use the flight information belongs to year 2008. If you read my my blog post series about BDCSCE, you should be familiar with it. Anyway, do not worry about the data structure, I use only a few columns of the data, and you get more information about it on the statistical computing website.

First, I’ll create a table on MySQL to store most active carriers (in 2008). I already set Zeppelin to access my MySQL database, so I create a new paragraph, put the following SQL commands and run them.

Using Zeppelin to Access MySQL

If you want to access MySQL Cloud Service using Zeppelin of Oracle Big Data Cloud Service Compute Edition (BDCSCE), you can use Spark DataFrames or Zeppelin interpreters. In this blog post, I’ll show how we can edit JDBC interpreter to connect MySQL Cloud Service.

First login to Oracle Big Data Cloud console, and go to “settings” tab, and open “notebook” section. You’ll see the interpreter settings. Search for “jdbc” and click “edit” button to edit the interpreter settings.