Let’s take a quick look at a very important and common experimental problem: checking if the difference in success rates of two Binomial experiments is statistically significant. This can arise in A/B testing situations such as online advertising, sales, and manufacturing.
rquery is already one of the fastest and most teachable (due to deliberate conformity to Codd’s influential work) tools to wrangle data on databases and big data systems. And now rquery is also one of the fastest methods to wrangle data in-memory in R (thanks to data.table, via a thin adaption supplied by rqdatatable).
The issue arises because wide tables (200 to 1000 columns) are quite common in big-data analytics projects. Often these are "denormalized marts" that are used to drive many different projects. For any one project only a small subset of the columns may be relevant in a calculation.