Connection aborts is happening in MariaDB 10.2 but not in 10.1 even with log_warnings level set to 2

Question

I am noticing different behavior in mariadb 10.1 & 10.2 reg.connection aborts.

I noticed connection getting aborted after 7 minutes(wait_timeout) of any query execution. There are few random connection aborts happening in my application too. But I don't see this behavior(connection abort logs) happening in mariadb 10.1.

I am aware that the default value for variable "log_warnings" has been changed from 1 to 2 in MariaDB 10.2. But even with log_warnings value as 2 in MariaDB 10.1, I don't see connection aborts happening.

For eg. In below query connection Id : 2218 is created

MariaDB [dummy]> show global variables like '%log%';
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    2218
Current database: dummy

From general query logs, the query executed time is 11:53:15

201222 11:53:15     6 Query     SHOW MASTER STATUS
                    6 Query     SHOW SLAVE STATUS
                    6 Query     UPDATE `oam`.`heartbeat` SET ts='2020-12-22T11:53:15.000830', file='mariadb-bin.000001', position='58352014', relay_master_log_file=NULL, exec_master_log_pos=NULL WHERE server_id='1'
                 2218 Connect   root@localhost as anonymous on dummy
                 2218 Query     show databases
                 2218 Query     show tables
                 2218 Field List        mytable
                 2218 Query     show global variables like '%wait%'

From Error logs, the connection closed at 12:00:16

2020-12-22 12:00:16 140673402672896 [Warning] Aborted connection 2218 to db: 'dummy' user: 'root' host: 'localhost' (Got timeout reading communication packets)

wait_timeout is set to 7mins(420s)

MariaDB [dummy]> show global variables like 'wait_timeout%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 420   |
+---------------+-------+
1 row in set (0.01 sec)

I could see the same behavior happening for any query execution (Connection aborting after 7mins) in MariaDB 10.2 but it is not happening in 10.1 even when the log_warnings level set to 2

Am I missing any configuration in 10.1 to observe these logs? or Any behavioral change that happened in 10.2 regarding this?

--EDIT--

We have the same wait_timeout configured in 10.1 as well (420s). In fact, we have kept most variable's values as same which might be the reason for the error as per the link https://dev.mysql.com/doc/refman/5.6/en/communication-errors.html.

| max_allowed_packet  | 33554432   | 
| max_connections       | 516   |
| thread_cache_size      | 256   |
| interactive_timeout    | 420   |

Answer 1

_{According to the general consensus that answers shouldn't be posted as comments, following my short answer.}

You have set a timeout of 7 minutes and your database instance is aborting the connection after 7 minutes. Works as designed.

General information is logged in the General query log and contains:

Established client connections and statements received from clients

The Error log contains:

Problems encountered starting, running, or stopping mysqld

^{Reference: 5.4 MySQL Server Logs (MySQL Documentation)}

So if your 10.1 installation is not displaying any errors, then you possibly have a larger timeout value set.