Cache invalidates after a while also when product or category edit is done.

[KooTjoo]

Preconditions

1. Magento 2.2.3
2. PHP 7.1
3. Plesk with Varnish 4.0 Docker
4. Running in Developer Mode (but also tested in Production)

Steps to reproduce

1. Activate Varnish or use Internal Page cache (result the same).
2. Warm the Cache
3. Check if CMS Pages, Category Pages and Product Pages are warmed.

Expected result

1. Cached pages shoukd stay warmed at least for few hours/a day depending on TTL that has been set.
2. Weh editing a product or category cache should not get flushed.

Actual result

1. After edit (product, category) all cache is gone.
2. After little while at about 30 minutes cache is invalidated.

I have tried all kinds of solutions but no luck.

Can this be a setup issue? Or is there a proper way to check this. When cache is there site is super fast.

[misha-kotov]

Expected Result: When editing a product or category cache should not get flushed.

This is not the case. According to our Varnish documentation:
The following actions can result in a Varnish purge:

• Maintaining a store (for example, adding or editing categories, prices, products, and promotional pricing rules). Varnish is purged automatically when you perform any of these tasks.

[KooTjoo]

@misha-kotov but this is strange, why not only recreate cache for product that has been edited, and why flush all te cache? If I edit a product my cms pages also get flushed. Really strange behavior that makes Magento almost unusable. I didn't have this with Magento 1.

[KooTjoo]

Isn't there a good way to troubleshoot these cache issues. We see a lot of people complaining about it. How do I disable all triggers that flush the cache to see if cach then persists.

[magento-engcom-team]

@KooTjoo, thank you for your report.
This seems to be correct Magento behavior. Please refer to the Community Forums or the Magento Stack Exchange site for advice or general discussion about this.
Otherwise you may submit Pull Request with the suggested changes.

[magento-engcom-team]

Hi @KooTjoo. Thank you for the report. We are moving your feature request to the special project. You can track this issue here: magento/community-features#66