Redis cache grows unilimmited

[toxix]

Preconditions (*)

1. Magento 2.3.3
2. Redis Cache enabled
3. Production mode

Steps to reproduce (*)

1. Run Magento in Production with 15 Stores and organic trafic
2. Redis caching enabled

Expected result (*)

1. Redis cache will stabilize in size.
2. Cache key expiery is set for all things that do have an expiery

Actual result (*)

1. Redis is growing in size to unlimited (>30GB)
2. Cache key expirey is not set

> info keyspace
# Keyspace
db0:keys=45775,expires=41711,avg_ttl=79567831
db1:keys=49089,expires=27837,avg_ttl=16355872
db2:keys=706,expires=706,avg_ttl=696476

Further information

The only way to prevent our production system server from dying was to set a hard limit for Redis memory consumption. The relying on the memory limit of redis has some performance impact and there are always things cleared that don't need to and vice versa. This should be handled by the application with setting an resonable ttl.

fix

This is actualy an known bug and already long time fixed in an dependency of magento core composer file. See also colinmollenhour/Cm_Cache_Backend_Redis@bc63e72
But this is not included in current magento version Last update of this core depedency was in September 2018: 32058c7

Applying this change as a hotfix, actualy stabalize our production redis at 3,5GB ram usage, instead of growing over 30GB. And also boost the performance of the system quiete a bit.

Hot Fix

Add the following requirement to your project composer.json file:

    "colinmollenhour/cache-backend-redis": "1.11.0 as 1.10.6"

Fix

I will File a PR with an updated composer dependency to the magento core and reference this issue.

[m2-assistant]

Hi @toxix. 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 2.3-develop instance - upcoming 2.3.x release

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

@toxix 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.

[PascalBrouwers]

@toxix Having the same problem but only at certain periods it will grow unlimited. I will see if your fix works too.

[kilis]

Same is also on Magento version 2.1.7. Did install only that fix, but nothing has really changed.

[magento-engcom-team]

Hi @toxix. Thank you for your report.
The issue has been fixed in #25488 by @toxix in 2.4-develop branch
Related commit(s):

• 49809a7af6493851d88e858cf5b7dcead56ec38e
• d4931eca33116a8dddba85ef6b139efa75b8bb5b
• 02edd9d1196659e6204c7839d400fbb4542b48c2
• 3b89fc4e0d5e6383ad05b1904ba1e3ccafd3950c
• 85e71f5745447fa083dd00b9f197fb6f49dd2327
• a8f1ee7a56fcb13496b4ea70dd906c61d66685e9
• 566c625ff5fbef7cabd64a6b9f9a78a15e857c4d
• 6d0fa267f2950dc6243a312d7a48d4b967be770e

The fix will be available with the upcoming 2.4.0 release.