What is Scalable Data Processing?

Elaborazione scalabile dei dati in R

Michael J. Kane and Simon Urbanek

Instructors, DataCamp

In this course ..

Work with data that is too large for your computer
Write Scalable code
Import and process data in chunks

RAM

All R objects are stored in RAM

How Big Can Variables Be?

"R is not well-suited for working with data larger than 10-20% of a computer's RAM." - The R Installation and Administration Manual

Swapping is inefficient

If computer runs out of RAM, data is moved to disk
Since the disk is much slower than RAM, execution time increases

Scalable solutions

Move a subset into RAM
Process the subset
Keep the result and discard the subset

Why is my code slow?

Complexity of calculations
Carefully consider disk operations to write fast, scalable code

Benchmarking Performance

library(microbenchmark)

microbenchmark( rnorm(100), rnorm(10000) )

Unit: microseconds
         expr    min      lq     mean  median      uq     max neval
   rnorm(100)   7.84   8.440   9.5459   8.773   9.355   29.56   100
 rnorm(10000) 679.51 683.706 755.5693 690.876 712.416 2949.03   100

Let's practice!

Elaborazione scalabile dei dati in R

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