Nested objects can come in handy in certain situations. Basically, with nested objects, Elasticsearch allows us to connect multiple documents together—one main document and multiple dependent ones. The main document and the nested ones will be indexed together and they will be placed in the same segment of the index (actually, in the same block), which guarantees the best performance we can get for data structure. The same goes for changing the document; unless you are using the update API, you need to index the parent document and all the other nested documents at the same time.

Now, let's get to our example use case. Imagine that we have a shop with clothes and we store the size and color of each t-shirt. Our standard, nonnested mappings will look similar...