Why do we need parent identities on frontend?

[madonzy]

I've noticed that we have plugin \Magento\ConfigurableProduct\Model\Plugin\ProductIdentitiesExtender::afterGetIdentities that is responsible to add parent tags for each child product. For example, that makes the product listing page much slower because we need to load the parent for each product on the page.

Why do we really need that on frontend? I tested and it PURGE cache for all child products when configurable product is saved.

[m2-assistant]

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[m2-assistant]

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[engcom-Hotel]

Hello @madonzy,

Thanks for the reporting and collaboration!

We request you to more elaborate on the issue so that we can reproduce it. Please provide us the below information:

• Environment information
• Steps to reproduce
• Expected and Actual result
• In case a specific use case, please provide those also
• Any screencast or screenshot

Thanks

[hostep]

Quoting from @sivaschenko's remark in another thread:

child products affect parent product representation while parent products do not affect child products representation on the frontend, so in order to be sure that the cache is valid - the cache of pages with parent products should be invalidated when a child product is changed.

For example, when a child product becomes out of stock or back in stock or is being enabled/disabled, it might influence how the parent product is being displayed on the frontend.

Does that answer your question @madonzy?

[madonzy]

@hostep not really. When child products become out of stock or enabled/disabled then child product cache tags are purged, and that means the cache of the category page will be purged. There's nothing to do with parent product in your examples.

[hostep]

I think I start to see your point, trying to fetch the parent products on the frontend makes not so much sense. But the afterGetIdentities method is also being called when a product is saved in the backoffice for example, and then it starts to make sense that for both the child and parent the caches are being purged, correct?

So if there is a performance problem here, it's that these lines should not be executed on the frontend, am I understanding this correctly?

[madonzy]

@hostep yeap. I think just disabling the plugin in the frontend scope di.xml will be a clean solution.

[engcom-Hotel]

@hostep thanks for helping us in understanding the issue.

Hello @madonzy,

We have looked into the code written here and tried to reproduce the issue by the following way:

1. Have some code changes to debug the issue as follows in the file named ProductIdentitiesExtender.php in line no.: 58:

$parentsidsbychild = $this->getParentIdsByChild($subject->getId());
        foreach ($parentsidsbychild as $parentId) {
            $parentProduct = $this->productRepository->getById($parentId);
            $parentProductsIdentities[] = $parentProduct->getIdentities();
        }

2. Search for the configurable product from Frontend i.e. Chaz Kangeroo Hoodie
3. Add a breakpoint in line no. 59 to check the value for the $parentsidsbychild variable, made in step 1.
4. It has been observed that code has not reached in foreach loop because the value of $parentsidsbychild is empty.
5. Even if we have tried it for the product detail page.
6. But the method afterGetIdentities is calling every time.

In the next scenario we have tried to check the performance of the page by enabling and disabling the plugin and we have seen the below difference in them. Please have a look at the below screenshot:

With Plugin:

Without Plugin

I just need to confirm if we are on the correct path or if we can reproduce the issue in some other way.

Thanks

[madonzy]

@engcom-Hotel first of all it's totally strange that you did not get the parent product id from the child product. The second is that you measure not only the request but everything that is not needed :)

Make sure that getParentIdsByChild is returning you the value and then got to the browser and test only document request time. Go to Network -> Document -> Select main loaded document -> Timing

P.S: Also, make sure you do not use any cache like Varnish or Built-in FPC in front