feat(medusa): Performance improvements of Carts domain

[adrien2p]

What

I have created a new method on the cart service which is addLineItems, allowing a user to add one or multiple items in an optimized way. Also updated the generate method from the line item service which now also accept a object data or a collection of data which. Various places have been optimized and cache support has been added to the price selection strategy.

The overall optimization allows to reach another 9000% improvement in the response time as a median (Creating a cart with 6 items):

	Min (ms)	Median (ms)	Max (ms)	Median Improvement (%)
Before optimisation	1200	9999	12698	N/A
After optimisation	63	252	500	39x
After re optimisation	56	82	399	121x
After including addressed feedback	65	202	495	49x

FIXES CORE-722

[changeset-bot]

🦋 Changeset detected

Latest commit: 17c90c4

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@medusajs/medusa	Patch

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[adrien2p]

Creating a cart with 6 items. Usually a user would create a cart and then call the create line item each time a customer add an item. But in cases where the cart is created with some items here are the results.

Before refactoring (single instance and process):

After refactoring (single instance and process):

[adrien2p]

Last result with the same env

[adrien2p]

After re optimization, especially the generate method from the line item service which can now manage to generate a batch of line items

[adrien2p]

[olivermrbl]

LGTM 💪

[adrien2p]

I ve closed and reopened the pr to trigger the pipeline to run again