[MDEV-30290] MariaDB crashes on Azure with query_cache_type enabled Created: 2022-12-22  Updated: 2023-02-05  Resolved: 2023-02-05

Status: Closed
Project: MariaDB Server
Component/s: Query Cache
Affects Version/s: 10.3.23
Fix Version/s: N/A

Type: Bug Priority: Major
Reporter: Willy de Zutter Assignee: Unassigned
Resolution: Incomplete Votes: 0
Labels: azure
Environment:

MariaDB on Azure, General Purpose, 4 vCore(s), 400 GB, probably running under some Windows Server version


 Description   

When query_cache_type is enabled the server frequently crashes. Since it runs on Azure I have no access to the logs and I did not get them when requested.

Azure support wrote this:
We got update from our engineering team that server was down because of query cache is not disabled. query_cache_type is a static variable and needs to restart the server to take it effect. So, can you please set query_cache_type parameter to OFF and query_cache_size as 0, and restart server as need to see if the variable query_cache_type as OFF.

The server is quite slow. A similar configuration on Googe Cloud (MySQL however) is much faster. I suspect this setting affects performance.

 Comments   
Comment by Alice Sherepa [ 2022-12-27 ]

Is it possible for you to upgrade to the recent version of MariaDB? The current version of 10.3 is 10.3.37 and there were a lot of bugs fixed since 10.3.23

Comment by Willy de Zutter [ 2022-12-27 ]

I can't upgrade, it's a SaaS, upgrading should be done by Azure people. They however claim that the issue is not yet resolved and should be resolved by the MariaDB Team, They are in a waiting pattern.

Comment by Alice Sherepa [ 2022-12-27 ]

Does the crash happen after a particular query? Is it possible for you to produce the test case to demonstrate the problem?

Comment by Willy de Zutter [ 2022-12-27 ]

Nou, it's completely random as far as I can tell. Sometimes it crashed after one minute, sometimes a couple of hours, but it keeps crashing when query_cache_type is on. We are using the database for webshops and API's and since I have no access to the logs I don't know the exact error or the first query that fails.

What I do know is that it started crashing when we moved to production. During testing the was less traffic thus less queries.

Comment by Alice Sherepa [ 2022-12-27 ]

There is not much we could do in this situation, it is the Azure-support task to report the bug to us then, with logs,etc

Comment by Willy de Zutter [ 2022-12-27 ]

I suspected as much.

I reopened my support issue with them and will link to this topic.

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