Cache IsProductAssignedToStock service to improve cart performance

[sky-hub]

Description (*)

While in cart or checkout page a large number of database queries are performed to check if a product is assigned to a specific stockId. Queries are correlated with the number of products in cart, more products, more queries for same product. The issue is manifested while Magento_Inventory module is enabled.
Tested on Magento Open Source 2.3.1

Query is: select stock_source_link.* from inventory_source_stock_link as stock_source_link join inventory_source_item on inventory_source_item.source_code = stock_source_link.source_code where (stock_source_link.stock_id = ?) and (inventory_source_item.sku = ?)

Fixed Issues (if relevant)

1. [Performance]Magento 2.3 Performance issue because of huge amount of mysql queries per products in cart #2496

Manual testing scenarios (*)

1. Add one product to cart
2. Navigate to checkout and check number of mysql requests in blackfire or any developer toolbar
3. Add another product to cart
4. Navigate to checkout/cart and compare number of mysql requests in blackfire or any developer toolbar

Questions or comments

N/A

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds are green)

[m2-community-project]

@sky-hub unfortunately, only members of the maintainers team are allowed to assign developers to the pull request

[ishakhsuvarov]

Hi @sky-hub

Thank you for the PR! I've got a couple of questions regarding this.

• Do you have any numbers with regards to optimized queries?
• Have you tested this only on default stock/source combination or with multiple stocks as well?

[sky-hub]

1. For two products in cart there are 18 queries and goes up for each added product.
2. Issue was tested only with sources. "Default Stock" is not assigned to products.

Note: If you would like to have a cache service injected in current interceptor instead of caching in interceptor, please let me know and i will update accordingly.

[ishakhsuvarov]

@sky-hub Current approach seems ok to me. Thanks for the numbers, appreciate your efforts.

I'll merge it once again with 2.3-develop to make sure it's good to go together with other set of patches and get it delivered shortly.