What is Apache Spark ?
An open-source distributed general-purpose cluster-computing framework for Big Data.
History of Apache Spark
2009: a distributed system framework initiated at UC Berkeley AMPLab by MateiZaharia
2010: Open sourced under a BSD license
2013: The project was donated to the Apache Software Foundation and the license was changed to Apache 2.0
2014: Became an Apache Top-Level Project. Used by Databricks to set a world record in large-scale sorting in November
2014-present: Exists as a next generation real-time and batch processing framework
Why Apache Spark
Data is exploded in volume, velocity and variety
The need to have faster analytic results becomes increasingly important
Support near real time analytics to answer business questions
Spark and Hadoop
Hadoop = HDFS(Hadoop Distributed File System) + MapReduce(data processing model)
Spark is advanced data processing/analysis model which is replacing MapReduce
Spark does not have its own file system so it run on the top of HDFS
Spark vs MapReduce
Easy to use
Supporting python. Java and Scala
Libraries for sql, ml, streaming
Batch like MapReduce is included
Interactive queries and streaming which return results immediately
In memory computations
Faster than MapReduce for complex application on disks
Resilient Distributed Datasets (RDDs)
Spark revolves around RDDs it is a fundamental data structure in spark.
It is an immutable distributed collection of objects which can be operated on in parallel.
Two ways to implement RDDs
1) Parallelizing an existing collection
2) Referencing a data set in an external storage system
Return a value to the driver program after running computation on data set
These examples and more are found at https://spark.apache.org/docs/latest/rdd-programming-guide.html
Using transformations ( flatmap, map, reduceByKey ) to build a data set of string and int pairs. It is then saved into a file
Finance and Stock trading Use Case
Imagine that you are working for a financial company and your job is to buy in and buy out stocks to make money. The decision you make highly depends on the prediction which is calculated by your financial model. In this kind of situation, how long it takes for your financial model to make a prediction is very critical. We know that the price of stocks change very fast. In a couple seconds a stock can change prices drastically. Thus, if your model cannot provide you a near real time response, you might lose your opportunity to trade your stocks with the best price. Apache Spark can be utilized to create financial models to make predictions in real time.