SQL on Hadoop
If you want to run a quick, ad-hoc query of all of that data sitting on your huge cluster, you could write a new Hadoop job which would take a bit of time. After programmers started doing this too often, they started pining for the old SQL databases, which could answer questions when posed in that relatively simple language of SQL. They scratched that itch, and now there are a number of tools emerging from various companies. All offer a faster path to answers.
Some of the most notable include: HAWQ, Impalla, Drill, Stinger, and Tajo. There are almost enough for another slideshow.