Most efficient way to model data in Elasticsearch

Elastic Stack Elasticsearch
1

I have an example of modelling an commence site. Say that the site has few hundreds shops and few millions products. The products per shop range: 1000-100.000 products/shop. I need to be able to aggregate the products and the shop fields. All the products and all the shops have the same schema.

Product

        {
          "productName"
          "price"
          "category"
        }

Shop

{
  "shopName"
  "rating"
}
  1. Is it more efficient to have a) 1 index/shop, b) same index and 1 type/shop or c) same index, same type and have a field to determine the shop of the product?

I read some related articles and most of them are in favour of same index and 1 type/shop. But then they say that if there is one single index which has a large number of docs it might be even slower than having multiple indices.

  1. I also need to perform JOINS and aggregations between the shops and the products. For example I need to be able to retrieve all the products from the shops with rating higher than 8/10 and also get the number of products per category. Is it preferable to use a) application-side JOIN, b) parent-child relationships, c) Siren plug-in, d) something else?
2
  1. Different indices.
  2. Why do you think you need joins?
3
  1. Thnx for that. Can you please elaborate a bit more on why you think 1 index is better/faster?
  2. Because first I need to get all the shops with rating above 8/10 and then join that with the products from these shops.
4

ES doesn't support joins. You have to model your data differently, typically by de-normalizing it.