Optimize loading in search indexers

[wychoong]

default loading is retrieving all fields of all variants
this changes only select only sku as only using sku in the indexer

could potentially breaking change if userland extended ProductIndexer and accessing other fields from $model->variants

TODO:

• customer indexer
• order indexer
• product option indexer
• document the changes in changelog Document search indexers changes docs#38

[wychoong]

@glennjacobs appreciate your input on this before working on it

[glennjacobs]

@glennjacobs appreciate your input on this before working on it

As we encourage devs to make their own indexers, do you think this is important?

[wychoong]

@glennjacobs appreciate your input on this before working on it

As we encourage devs to make their own indexers, do you think this is important?

I think is the out of the box experience.
In my use case, I have a project is to sync data from external system, where a product can up to 500 variants, and on top of that it needs to merge a few products into single product in lunar. So when the catalog is huge and fetching a lot of data from relationships, the scout command just died halfway.

For now I replaced with own indexer, with the minor change as per this PR, because the default already good enough.

For the normal use case probably doesn’t feel it.

[glennjacobs]

The breaking change is my concern here. I'm torn :-) I guess v1.5 is a big update, so what's one more breaking change?!

[wychoong]

The breaking change is my concern here. I'm torn :-) I guess v1.5 is a big update, so what's one more breaking change?!

I think it should be easy upgrade as long as documented.

Optimized for those using default. Those making their own would be a minor change in their custom indexer.

[glennjacobs]

@wychoong I'm happy for you to finish up this PR

[wychoong]

@wychoong I'm happy for you to finish up this PR

done, with the changelog updated lunarphp/docs#38