Magento very slow after upgrade to 2.3.4 community

[alex9434]

Preconditions (*)

1. Magento 2.3.4 community (upgrade from 2.3.3
2. PHP 7.3, nginx, varnish, redis on Devuan Ascii

Steps to reproduce (*)

1. Upgrade magento from 2.3.3 according to https://devdocs.magento.com/guides/v2.3/comp-mgr/cli/cli-upgrade.html
2. Website extremely slow (google lighthouse times out). CLI also very slow, e.g. magento cache:clean takes 5 min

Expected result (*)

1. Speed comparable to 2.3.3
2. I don't know how to find the root cause of the slow speed

Actual result (*)

1. Website has become very slow

[m2-assistant]

Hi @alex9434. Thank you for your report.
To help us process this issue please make sure that you provided the following information:

• Summary of the issue
• Information on your environment
• Steps to reproduce
• Expected and actual results

Please make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, please, add a comment to the issue:

@magento give me 2.4-develop instance - upcoming 2.4.x release

For more details, please, review the Magento Contributor Assistant documentation.

@alex9434 do you confirm that you were able to reproduce the issue on vanilla Magento instance following steps to reproduce?

• yes
• no

---

• Join Magento Community Engineering Slack and ask your questions in #github channel.

[bahramdavoodi]

@alex9434, you can check with blackfire or some tool. maybe you installed some extension or ...
also check your magento cache status.

[Swahjak]

This might be a duplicate of #26692 (#26809 also complaining about higher resource usage, but seems to be contained to cron).

[m2-assistant]

Hi @engcom-Alfa. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

• 1. Verify that issue has all the required information. (Preconditions, Steps to reproduce, Expected result, Actual result).

  Details

  If the issue has a valid description, the label Issue: Format is valid will be added to the issue automatically. Please, edit issue description if needed, until label Issue: Format is valid appears.

• 2. Verify that issue has a meaningful description and provides enough information to reproduce the issue. If the report is valid, add Issue: Clear Description label to the issue by yourself.

• 3. Add Component: XXXXX label(s) to the ticket, indicating the components it may be related to.

• 4. Verify that the issue is reproducible on 2.4-develop branch

  Details

  - Add the comment @magento give me 2.4-develop instance to deploy test instance on Magento infrastructure.
  - If the issue is reproducible on 2.4-develop branch, please, add the label Reproduced on 2.4.x.
  - If the issue is not reproducible, add your comment that issue is not reproducible and close the issue and stop verification process here!

• 5. Add label Issue: Confirmed once verification is complete.

• 6. Make sure that automatic system confirms that report has been added to the backlog.

[engcom-Alfa]

Duplicate of #26692