Fix N+1 queries when updating non-translated model attributes

[derekmd]

One of the joys outcomes of Laravel Telescope is discovering cron jobs that have been causing a nightmare-ish number of N+1 database queries.

I have a (partially) translated model with a boolean status column frequently updated. Yesterday I discovered this package lazy-loads the $this->translations relationships even when there aren't changes to non-translated attributes.

To give you an idea of scale, it was 500k+ redundant translation SELECT database queries run in a 15min period every day.

e.g.,

App\PressRelease::first()->save()

^ that needlessly lazy-loads relationship PressRelease@translations when neither translated attributes nor "regular" Eloquent model attributes are flagged as dirty.

This pull request adds a check on Illuminate\Database\Eloquent\Model@relationLoaded('translations')
when saving the model. An Eloquent relationship's models can't be marked "dirty" if they have yet to be loaded into PHP memory.

[Gummibeer]

Thanks for your PR! Your changes look good. I will merge it later and before releasing I will adjust some code duplicates in the save() method.
So far I know there is also a way to check the amount of executed queries in phpunit. Will check this out - your current test works but doesn't test your issue/bug in a direct way. If I find a way I won't change your test but add a second one because your current one is also a good test.

[derekmd]

• Added $this->assertCount(..., DB::getQueryLog()) to inspect queries if that's what you're looking for.
• I also added a second commit to remove the duplicate save() conditional branch.

[Gummibeer]

Great work! Yes this is what I want. 🎉
I will have to review this later on my development PC - I think monday. But so far it looks good. 😊

[Gummibeer]

https://github.com/dimsav/laravel-translatable/releases/tag/v9.3.0