What's the table design used to store features?

[damnko]

Hi all, I have a use case where I'd want to store multiple features with their related metadata and was wondering if this is possible with feast and how this is handled in the framework.

Let's consider an example scenario where we want to store features related to a shop chain (item purchases, orders cancelled...), but each feature also has some metadata attached to it eg. product name, customer class, etc. In a standard scenario (without leveraging feast) I would handle it this way with a table storing the features and one storing the metadata for each feature name.

feature_store_table

event_date	store_name	feature_name_hash	feature_value	creation_date
2021-01-01	food_corp	feature_1	10	2021-05-01
2021-01-01	food_corp	feature_2	5	2021-05-01
2021-01-01	supplements_corp	feature_1	8	2021-05-01
2021-01-01	supplements_corp	feature_2	3	2021-05-01
2021-01-01	food_corp	feature_3	2	2021-05-01

feature_metadata_table

feature_name_hash	feature_name	metadata_name	metadata_value
feature_1	items_sold	product_name	cheese
feature_1	items_sold	customer_class	french
feature_2	items_sold	product_name	cheese
feature_2	items_sold	customer_class	german
feature_3	orders_cancelled	customer_class	french

My questions are:

1. Is this flexibility available in feast? Or each combination of feature_name + metadata_name + metadata_value would have to be a separate feature (and as per my current understanding, a separate table)?
2. What's the table schema/design used by feast to store features? Does it use a tall/narrow format or a short/wide one?

Thanks for your help