What is NoSQL?
Key-Value Stores memcached is a “big hash in the sky” – it is a key value store. Similarly, NoSQL key-value stores “add to that big hash in the sky” and store to disk. Speaker’s favorite is Redis because it’s similar to memcached. • key-value store + datatypes (list, sets, scored sets, soon hashes will be there) • cache-like functions (like expiration) • (Mostly) in-memory Another interesting key-value store is Riak • Combination of key-value store and document database • heavy into HTTP REST • You can create links between documents, and do “link walking” that you don’t normally get out of a key-value store • built-in Map Reduce Map Reduce: • Massively parallel way to process large datasets • First you scour data and “map” a new set of dataM • Then you “reduce” the data down to a salient result — for example, map reduce function to make a tag cloud: map function makes an array with a tag name and a count of 1 for each instance of that tag, and the reduce tag goes through that array and
