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Big data with Modern R & Spark in Public Statistics

"SEMINAR: Análisis de Big data con Tidyverse y Spark: uso en estadística pública"
By Xavier de Pedro Puente, Ph.D.
Technician at the Municipal Data Office. Barcelona City Council.

Image

Monday September 14, 2020. 16h-17:30h + questions
Within the context of the postgraduate course on
"Data Science. Applications to Biology and Medicine with Python and R"
at University of Barcelona. 2020.


IImage from https://blog.rstudio.com/2019/03/15/sparklyr-1-0/

Start Slideshow Presentation

Outline

  1. About me
  2. Barcelona City Council Çase
  3. Modern R: Tidyverse
  4. Modern R & Big Data
  5. Spark (Apache) & Sparklyr (RStudio)
  6. Alternative approach


== (1) About me ==

Xavier de Pedro Puente, Ph.D. xavier.depedro (a) seeds4c.org

  • Academics:
    • Degree in Biology (UB)
    • Ph.D. in Ecology (UB)
    • Postgraduate in Bioinformatics (UOC)
  • Current Work:
  • Past (related) Work:
    • Bioinformatics technician (UEB, VHIR)
    • Systems administrator (UEB, VHIR)

Disclaimer The views expressed in this presentation are those of the author and do not necessarily represent the views and policies of the Barcelona City Council. Any mention of trade names, products or services does not imply an endorsement by the Barcelona City Council unless explicitly stated as such.

== (2) Barcelona City Council Case ==

  • 2018: OMD - Municipal Data Office opened (details):
    Management, quality, governance and use of data controlled and/or stored by Barcelona City Council and all of its associated bodies (both public and private).
    .
  • Public Statistics portal
  • Recent product: Covid-19 in BCN monitoring with an R Shiny App


Ajbcn Covid19 Shiny App 01 En

Barcelona City Council: Public money - public code


There is a Government policy for open source and agile methodologies

Ajbcn Publicmoneypubliccode 00

Barcelona City Council: CityOS

City Council's infrastructure based on open-source Big Data technology

City OS: internal data management, known as "Data Lake"


Ajbcn Cityos Francesca Bria 00
Image from Francesca Bria (Barcelona Digital City Roadmap 2017-2020)

Barcelona City Council: CityOS Technologies

CityOS technologies: GNU/Linux, CentOS, Cloudera, Activiti, Talend, Protégé, R, Zabbix, Nagios, Ganglia

Ajbcn Cityos Technologies Github Jberdonces 00


Source: https://github.com/AjuntamentdeBarcelona/CityOS_AjBCN - Image from J. Berdonces a Github

Barcelona City Council: CityOS - Cloudera Manager

Cloudera with Hadoop File System, Hue, HBase, Hive, Impala, Oozie, Spark, Yarn, Kafka, ...

Ajbcn Cityos Technologies Github Jberdonces 01 Cloudera Manager

Source: https://github.com/AjuntamentdeBarcelona/CityOS_AjBCN - Image from J. Berdonces a Github

== (3) From Base R to "Modern R": Tidyverse ==


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Modern R (Tidyverse)

Workflow, Packages, People/Community

Image Image Image


Derived from here & here

Modern R (Tidyverse) principles

  1. Main structures are ordered data
    • Each variable is saved in its own column.
    • Each observation is saved in its own row.
    • Each "type" of observation stored in a single table
  2. .Each function represents one step
  3. Functions are combined with the pipe operator %>%
  4. Each step is a query or command
Tidyverse Pivot Longer Example 02


Derived from here, here & here

== (4) Modern R & Big Data ==

Data > RAM = Problem
Rstudio Bigdata Analytics Example Data Higher Than RAM

From an RStudio seminar by Garrett Grolemund

3 classes of Big Data Problems


Rstudio Bigdata Analytics Class1
Rstudio Bigdata Analytics Class2
Rstudio Bigdata Analytics Class3

From an RStudio seminar by Garrett Grolemund


R interacts with other technologies

Rstudio Bigdata Analytics Ecosystem

From an RStudio seminar by Garrett Grolemund

R General Strategy (i): Class 1 & 2

Rstudio Bigdata Analytics General Strategy 1 All

From an RStudio seminar by Garrett Grolemund

R General Strategy (ii): Class 1 & 2

Rstudio Bigdata Analytics General Strategy 2 All

From an RStudio seminar by Garrett Grolemund

R General Strategy (iii): Class 3

Rstudio Bigdata Analytics General Strategy 3 All

From an RStudio seminar by Garrett Grolemund

Class 3 - dbplyr

R - tidyverse - dplyr + dbplyr
Rstudio Bigdata Analytics Example 02 Dplyr

From an RStudio seminar by Garrett Grolemund

R General Strategy (iv): Recap

Rstudio Bigdata Analytics Recap

From an RStudio seminar by Garrett Grolemund

== (5) Spark (Apache) & sparklyr (Rstudio) ==

  • Spark, from Apache Foundation: a leading tool that is democratizing our ability to process large datasets.
  • R Packages:
    • Apache introduced an interface for the R computing language: SparkR R package
    • RStudio introduced sparklyr R package: a project merging R and Spark into a powerful tool that is easily accessible to all.
  • But why where they introduced?
  • And why 2 different packages?


Derived from here & here

Digital information vs analog information | World Bank - 2003

  • World Bank report: digital information surpassed analog information around 2003.
    • 10 million terabytes of digital information (~ 10 million storage drives today)
    • our footprint of digital information is growing at exponential rates.


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From "The R In Spark" (book)

Google File System | Google - 2003

  • Search engines were unable to store all of the web page information required to support web searches in a single computer.
  • They had to split information into several files and store them across many machines
  • This approach became known as "Google File System", due to a research paper published in 2003 by Google.


From "The R In Spark" (book)

MapReduce | Google - 2004

  • 2004: Google published a new paper describing how to perform operations across the Google File System:
    • approach called "MapReduce"
      • map operation: arbitrary way to transform each file into a new file
      • reduce operation: combines two files
    • Both operations require custom computer code, but the MapReduce framework takes care of automatically executing them across many computers at once.
    • Sufficient to process all the data available on the web, while providing flexibility to extract meaningful information from it.


From "The R In Spark" (book)

Hadoop Distributed File System (HDFS) | Yahoo - 2006

  • A team at Yahoo implemented the Google File System and MapReduce as a single open source project, released in 2006 as Hadoop
    • Google File System implemented as the Hadoop Distributed File System (HDFS).
  • The Hadoop project made distributed file-based computing accessible to a wider range of users and organizations, making MapReduce useful beyond web data processing.


Image

From "The R In Spark" (book) | Image from De Apache Software Foundation, with Apache License 2.0

Hive | Facebook - 2008

  • Hadoop provided support to perform MapReduce operations over a distributed file system, but it still required MapReduce operations to be written with code every time a data analysis was run
  • Hive project (2008, by Facebook) brought Structured Query Language (SQL) support to Hadoop.
    • Data analysis could now be performed at large scale without the need to write code for each MapReduce operation


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From "The R In Spark" (book) | Image from Davod with Apache License 2.0

Spark (closed sourced) | UCBerkely - 2009

  • In 2009, Spark began as a research project at UC Berkeley’s AMPLab to improve on MapReduce.
    • Spark provided a richer set of verbs beyond MapReduce to facilitate optimizing code running in multiple machines.
    • Spark also loaded data in-memory, making operations much faster than Hadoop’s on-disk storage.


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From "The R In Spark" (book)

Spark: In-memory and on-disk

  • Spark: well known for its in-memory performance, but designed to be a general execution engine that works both in-memory and on-disk
    • For instance, Spark has set sorting, for which data was not loaded in-memory, but using improvements in network serialization, network shuffling, and efficient use of the CPU’s cache to dramatically enhance performance.
    • If you needed to sort large amounts of data, there was no other system in the world faster than Spark.


From "The R In Spark" (book)

Spark: faster and easier

  • Spark is much faster, more efficient, and easier to use than Hadoop.
  • Speed Example:
    • Without Spark: it takes 72 minutes and 2,100 computers to sort 100 terabytes of data using Hadoop,
    • With Spark: only 23 minutes and 206 computers
  • Simplicity example: word-counting MapReduce example takes:
    • about 50 lines of code in Hadoop, but
    • only 2 lines of code in Spark.

Hadoop Record Spark Record
Data Size 102.5 TB 100 TB
Elapsed Time 72 mins 23 mins
Nodes 2100 206
Cores 50400 6592
Disk 3150 GB/s 618 GB/s
Network 10Gbps 10Gbps
Sort rate 1.42 TB/min 4.27 TB/min
Sort rate / node 0.67 GB/min 20.7 GB/min


From "The R In Spark" (book)

Spark (open sourced) - 2010 | Apache Foundation - 2013

  • 2010: open sourced. 2013: donated to the Apache Software Foundation
  • Apache Spark is a unified analytics engine for large-scale data processing
    • Unified: supports many libraries, cluster technologies, and storage systems.
    • Analytics: discovery & interpretation of data to communicate information
    • Engine: expected to be efficient and generic.
    • Large-Scale: as cluster-scale (set of connected computers working together).

Image Image


From "The R In Spark" (book) | Image from the Apache Software Foundation, with Apache License 2.0

SparkR (Base R) vs. sparklyr (Modern R)

Feature SparkR sparklyr
Data input & output+ ++ +
Data manipulation-+ + +
Documentation+ ++ +
Ease of setup+ ++ +
Function naming- -+ + +
Installation++ +
Machine learning++ +
Range of functions+ + ++ +
Running arbitrary code++ +
Tidyverse compatability- - -+ + +


From https://www.eddjberry.com/post/2017-12-05-sparkr-vs-sparklyr/

Sparklyr | RStudio

  • Sparklyr, from Rstudio: https://spark.rstudio.com/
  • R interface for Apache Spark, agnostic to Spark versions,
    • 2016: 1st version released (v0.4)
  • Easy to install, serving the R community,
  • Embracing other packages & practices from the R community (tidyverse, ...)
  • Designed for: New Users, Data Scientists, and Expert Users


Hdfs Sparklyr Approach 00

Image from here

Summary: Big Data with Modern R & Spark

Big Data with Modern R & Spark in context

Hdfs Hive Sparklyr Approach 01 Bigger Picture

Image from here

Speeding up Spark via R with Apache Arrow

Apache Arrow is a cross-language development platform for in-memory data, you can read more about this in the Arrow and beyond blog post. In sparklyr 1.0, we are embracing Arrow as an efficient bridge between R and Spark, conceptually.

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X Axis: Time to complete task (left-hand-side is faster)
Y Axis: Top section: WITHOUT Apache Arrow), Bottom section: WITH apache Arrow.

Copying:
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Collecting:
Image
Transforming
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From: https://arrow.apache.org/blog/2019/01/25/r-spark-improvements/

== (6) Addendum: Diskframe as potential alernative for medium sized projects? ==

  • disk.frame package, answer to: how do I manipulate structured tabular data that doesn’t fit into Random Access Memory (RAM)?.
  • It makes use of two simple ideas Image
    1. split up a larger-than-RAM dataset into chunks and store each chunk in a separate file inside a folder and
    2. provide a convenient API to manipulate these chunks
  • It performs a similar role to distributed systems such as Apache Spark, Python’s Dask, and Julia’s JuliaDB.jl for medium data which are datasets that are too large for RAM but not quite large enough to qualify as big data.


More information: here and here

References

Thanks

xavier.depedro (a) seeds4c.org


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