We first receive the order ID and the total amount of the order, and then we receive the line items of the order. The first value is the item ID, the second is the order ID, (which matches the order ID value) and then the cost of the item. In this example, we have two orders. The first one has four items and the second one has only one item.
The idea is to hide all of this from our Spark application, so what it receives on the DStream is a complete order defined on a stream as follows:
Check out this practical application of Spark Streaming.
Business users have been content to perform analytics on data collected in Amazon Redshift to spot trends. But recently, they have been asking AWS whether the latency can be reduced for real-time analysis. At the same time, they want to continue using the analytical tools they’re familiar with.
In this situation, we need a system that lets you capture the data stream in real time and use SQL to analyze it in real time.
In the earlier section, you learned how to build the pipeline to Amazon Redshift with Firehose and Lambda functions. The following illustration shows how to use Apache Spark Streaming on EMR to compute time window statistics from DynamoDB Streams. The computed data can be persisted to Amazon S3 and accessed with SparkSQL using Apache Zeppelin.
There are a lot of technologies at play here and it’s worth a perusal, even though I’m going to keep recommending that you use a relational database like SQL Server for OLTP work in all but the most extreme of circumstances.
We’ll aim to predict the volume of events for the next 10 minutes using a streaming regression model, and compare those results to a traditional batch prediction method. This prediction could then be used to dynamically scale compute resources, or for other business optimization. I will start out by describing how you would do the prediction through traditional batch processing methods using both Apache Impala (incubating) and Apache Spark, and then finish by showing how to more dynamically predict usage by using Spark Streaming.
Of course, the starting point for any prediction is a freshly updated data feed for the historic volume for which I want to forecast future volume. In this case, I discovered that Meetup.com has a very nice data feed that can be used for demonstration purposes. You can read more about the API here, but all you need to know at this point is that it provides a steady stream of RSVP volume that we can use to predict future RSVP volume.
This is pretty dense, but it is a great look at one potential architecture leveraging Spark and several tools in the Hadoop ecosystem.
One thing we are proud of in Spark is creating APIs that are simple, intuitive, and expressive. Spark 2.0 continues this tradition, with focus on two areas: (1) standard SQL support and (2) unifying DataFrame/Dataset API.
On the SQL side, we have significantly expanded the SQL capabilities of Spark, with the introduction of a new ANSI SQL parser and support for subqueries. Spark 2.0 can run all the 99 TPC-DS queries, which require many of the SQL:2003 features. Because SQL has been one of the primary interfaces Spark applications use, this extended SQL capabilities drastically reduce the porting effort of legacy applications over to Spark.
There’s some great stuff coming out of DataBricks. Spark 2.0 looks to be an exciting product.
However, the logs can be corrupted. For example, the second line is a blank line, the fourth line reports some network issues and finally the last line shows a sales value of zero (which cannot happen!).
We can use accumulators to analyse the transaction log to find out the number of blank logs (blank lines), number of times the network failed, any product that does not have a category or even number of times zero sales were recorded. The full sample log can be found here.
Accumulators are applicable to any operation which are,
1. Commutative -> f(x, y) = f(y, x), and
2. Associative -> f(f(x, y), z) = f(f(x, z), y) = f(f(y, z), x)
For example, sum and max functions satisfy the above conditions whereas average does not.
Accumulators are an important way of measuring just how messy your semi-structured data is.
When creating Apache Spark applications the basic structure is pretty much the same: for sbt you need the same
build.sbt, the same imports, and the skeleton application looks the same. All that really changes is the main entry point, that is the fully qualified class. Since that’s easy to automate, I present a couple of shell scripts that help you create the basic building blocks to kick-start Spark application development and allow you to easily upgrade versions in the configuration.
Check these out if you’re interested in Spark.
As Mario Inchiosa and Roni Burd demonstrate in this recorded webinar, Microsoft R Server can now run within HDInsight Hadoop nodes running on Microsoft Azure. Better yet, the big-data-capable algorithms of ScaleR (pdf) take advantage of the in-memory architecture of Spark, dramatically reducing the time needed to train models on large data. And if your data grows or you just need more power, you can dynamically add nodes to the HDInsight cluster using the Azure portal.
I don’t normally link to webinars (because they tend to violate my “should be viewable in a coffee break” rule of thumb) but I have a soft spot in my heart for these technologies. If you want to dig into more “mainstream” (off the Microsoft platform) Spark + R fun, check out SparkR.
Power BI can connect to many data sources as you know, and Spark on Azure HDInsight is one of them. In area of working with Big Data applications you would probably hear names such as Hadoop, HDInsight, Spark, Storm, Data Lake and many other names. Spark and Hadoop are both frameworks to work with big data, they have some differences though. In this post I’ll show you how you can use Power BI (either Power BI Desktop or Power BI website) to connect to a sample of Spark that we built on an Azure HDInsight service. by completing this section you will be able to create simple spark on Azure HDInsight, and run few Python scripts from Jupyter on it to load a sample table into Spark, and finally use Power BI to connect to Spark server, load, and visualize the data.
If you’re totally unfamiliar with Spark but interested in data processing, now’s a good time to start digging into the topic.