MySQL stop suddenly

Hi,
Mysql stop suddenly check the log and I have the following:

WARN: HikariPool-1 - Connection com.mysql.cj.jdbc.ConnectionImpl@37fd8833 marked as broken because of SQLSTATE(08S01), ErrorCode(0) - Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost. - EOFException (... < QueryBuilder:446 < DataManager:425 < DefaultDataHandler:40 < ...)
2021-03-31 22:03:18  WARN: Failed to store position - Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost. - EOFException (... < QueryBuilder:446 < DataManager:425 < DefaultDataHandler:40 < ...)
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@630021bd (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@92298a9 (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@524535ae (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@2922fc2a (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@4bcd3d7a (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@5637137a (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@2d24a457 (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@13d9ce75 (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:18  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@57917fb3 (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2021-03-31 22:03:48  WARN: Failed to update device - Connection refused (Connection refused) - ConnectException (...)

Any idea.

Sounds like MySQL issue. Is there a reason you are asking on this forum instead of MySQL related resources?

Probably because like me, he set up Traccar with the recommended MySql database with the supplied settings and it fails just like that.. I used the suggested Docker setup.
I've added "spring.datasource.hikari.max-lifetime=500000" to the url connection string from this page https://www.traccar.org/mysql/ and so far seems to be OK.
Source: https://stackoverflow.com/questions/60310858/possibly-consider-using-a-shorter-maxlifetime-value-hikari-connection-pool-spr/60380157#60380157

fyi, for the record, this didn't fix the issue.. I have since removed the spring.datasource.hikari.max-lifetime..

so still an issue..

So, today's test is I have added to new .cnf file to the docker volume that maps to /etc/mysql/conf.d

and added this (which is double the default time which I confirmed was set to 28800):

[mysqld]
wait_timeout=57600

I restarted MySql and confirmed this has taken effect:
SHOW global VARIABLES LIKE 'wait_timeout';

And then restarted Traccar..

One possible reason why I (alone?) might be getting this, is I'm running in a Docker Swarm.. this is mentioned in this thread due to a TCP idle timeout:
https://github.com/MariaDB/mariadb-docker/issues/113

Changing the MySql timeout from 8 hours to 16 hours is unlikely to fix this as the TCP idle timeout is supposedly 15 mins..

So also referring to this https://flavio.aiello.ch/mariadb-automatic-docker-limits/, the max timeout should be less than 15 mins (900 seconds) to cater for the network timeout..

I have changed the timeout to 750 seconds as per last article and re-started.. I'll check over the coming days to see if this is now resolved.

If you need alternative ideas, check this thread: https://github.com/moby/moby/issues/37822

Logically this makes sense now.. stay tuned.

ps - is there a post size limit?? I had to split above to 3 messages to get them to save.. otherwise I got 'forbidden'.

There's no post limit, but there's a limit on number of URLs in a comment.

that's handy..

Sadly, this is still unresolved.. I also have added
spring.datasource.hikari.maxLifetime=750000
to the database.url in the traccar.xml

I don't get an error though.. just this warning.. is it losing data?

2023-07-13 13:42:37  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@66e48648 (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2023-07-13 13:42:37  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@682364e4 (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.
2023-07-13 13:42:37  WARN: HikariPool-1 - Failed to validate connection com.mysql.cj.jdbc.ConnectionImpl@6c1ced38 (No operations allowed after connection closed.). Possibly consider using a shorter maxLifetime value.

We don't use spring, so I'm not sure why you keep using that config parameter. It won't do anything at all.