Cronjobs increasing CPU usage and slow queries

[Zyles]

Cronjobs stuck in pending state. CPU usage increasing. Mysql slow queries increasing.

Time is 13:28.

Logs filled with:

use magento;
SET timestamp=1579781526;
SELECT GET_LOCK('|CRON_GROUP_default', '5');
# Time: 200123 13:13:06
# User@Host: magento[magento] @ localhost []
# Thread_id: 20330  Schema: magento  QC_hit: No
# Query_time: 2.951003  Lock_time: 0.000000  Rows_sent: 1  Rows_examined: 0
# Rows_affected: 0
SET timestamp=1579781586;

Load goes down after disabling cronjob in crontab:

Preconditions (*)

Magento 2.3.3 & 2.4-develop
PHP-FPM 7.2.24

Steps to reproduce (*)

1. Install Magento
2. Setup cron jobs
3. Run store for a week
4. Break store

Expected result (*)

Normal working store.

Actual result (*)

1. Increased CPU usage
2. Increased cronjobs count
3. Increased slow queries
4. Slow store

[m2-assistant]

Hi @Zyles. 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

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

• yes
• no

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[gwharton]

Do ypu have any jobs stuck "running"

[devchris79]

We see some cron jobs stuck in the running status:

That's with a Magento 2.3.3 installation.

[gwharton]

If you manually delete the rows that are stuck running, the pending jobs should be cleaned back to normal levels over the next few cron runs.

[gwharton]

But you need to look at why they do not complete. It would be better if magento had some timeout to terminate stuck running jobs.

[devchris79]

I have deleted them out before, but they returned (as I suppose you would expect). I will try again and try to understand the sticking.

I agree with the timeout to terminate stuck routines, that would be great. I also don't understand why we have routines stuck in the "running" state with no execution time stamp, surely that should be the first thing done....

[Zyles]

Didn't check "running". Truncated table as it took up too much server resources.

Clearly a bug.

One should not routinely have to empty the table manually.

[m2-assistant]

Hi @engcom-Hotel. Thank you for working on this issue.
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