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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   |
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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.

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  • 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 dev.mysql.com/doc/refman/5.6/en/communication-errors.html. Eg:| max_allowed_packet | 33554432 | | max_connections | 516 | | thread_cache_size | 256 | | interactive_timeout | 420 | Dec 23 '20 at 11:31
  • @ragulrangarajan Could you post the comment information in your question by hitting the edit link? It's (possibly) relevant. And then you might want to compare these values for both instances and add to your initial post. If you have any other relevant information then please add this to your question. Comments don't read very well, and this could lead to your question being closed. Thanks.
    – John K. N.
    Dec 23 '20 at 11:54

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