As the kingdom grew, the Guide expanded. It introduced , which allowed scribes to write simple scripts instead of complex MapReduce codes, and Hive , which let people talk to the crates using the old "SQL" language they already knew.
Once upon a time, in the rapidly expanding kingdom of Data, there was a growing crisis. The kingdom’s traditional filing cabinets—known as Relational Databases—were bursting at the seams. Every day, more scrolls arrived than the royal scribes could sort, and the cost of buying bigger, sturdier cabinets was threatening to bankrupt the treasury.
But what if a crate broke? The Guide revealed a clever trick: . Every piece was copied three times and stored in different parts of the warehouse. If a shelf collapsed, the data wasn't lost; the army just looked at the backup. Chapter 2: The Great Sorting Party (MapReduce) Hadoop: The Definitive Guide
Every scribe in the warehouse was given a small pile of scrolls and told to count specific words. They did this all at once, in parallel.
The kingdom of Data stopped fearing the flood of scrolls. They learned that you don't need the most expensive machinery to handle big problems; you just need a smart way to break the work apart and a yellow elephant to lead the way. As the kingdom grew, the Guide expanded
The Guide first described (Hadoop Distributed File System). Instead of trying to fit a massive scroll into one crate, Hadoop would chop the scroll into pieces and spread them across hundreds of crates.
The scribes then traded their notes so that all the "A" counts went to one table and all the "B" counts went to another. The Guide revealed a clever trick:
It brought in for those who needed to find a specific line in a scroll instantly, and Zookeeper to make sure all the different parts of the army didn't trip over each other. The Moral of the Story