Finally, I am using the below setting file to avoid "Error: MySQL server has gone away" message. 
I have not been getting the message for 3 days (as an aging test). 
Here is the related configuration files that have to be modified for Ubuntu 16.04.1 & Mariadb Server 10.0. 

mytizen$sudo vi /etc/mysql/conf.d/mysqldump.cnf
mytizen$sudo vi /etc/mysql/mariadb.conf.d/50-server.cnf
mytizen$sudo vi /etc/mysql/mysql.conf.d/mysqld.cnf

----------- content -------------------------------------
# * Fine Tuning
# max_allowed_packet: from 16M to 128M
max_allowed_packet      = 128M
#  timeout: from 28800 (8h) to 2592000 (30days)
wait_timeout            = 2592000
interactive_timeout     = 2592000
-----------------------------------------------------------

The below is how we check the values if the modified valued is applied to Mariadb server. 
MariaDB [(none)]> 
MariaDB [(none)]> SELECT @@global.wait_timeout, @@global.interactive_timeout, @@session.wait_timeout, @@session.interactive_timeout;
+-----------------------+------------------------------+------------------------+-------------------------------+
| @@global.wait_timeout | @@global.interactive_timeout | @@session.wait_timeout | @@session.interactive_timeout |
+-----------------------+------------------------------+------------------------+-------------------------------+
|               2592000 |                      2592000 |                2592000 |                       2592000 |
+-----------------------+------------------------------+------------------------+-------------------------------+
1 row in set (0.00 sec)

MariaDB [(none)]> 
MariaDB [(none)]> 
MariaDB [(none)]> show variables like 'max_allowed_packet';
+--------------------+-----------+
| Variable_name      | Value     |
+--------------------+-----------+
| max_allowed_packet | 134217728 |
+--------------------+-----------+
1 row in set (0.00 sec)

MariaDB [(none)]> 
 



On Tue, Apr 11, 2017 at 3:34 PM, Geunsik Lim <leemgs@gmail.com> wrote:
4 hours is passed. The web-based service is okay with "wait_timeout=8hours" and "max_allowed_packet=100MB"
I am planning to execute aging test for 3 days at least. 

BTW, Can we check inactivity time (e.g., wait_timeout) that MariaDB waits
before it will be close a connection with "mytop" command like the below content?


u164.04$ mytop -u root -p*** [enter]

MySQL on localhost (10.0.29)             load 0.24 0.26 0.27 1/563 18515 up 0+23:47:16 [15:22:38]
 Queries: 5.2k     qps:    0 Slow:     0.0         Se/In/Up/De(%):    07/00/00/00 
 Sorts:      0 qps now:    1 Slow qps: 0.0  Threads:    3 (   1/   1) 00/00/00/00 
 Key Efficiency: 100.0%  Bps in/out:   1.7/233.2   Now in/out:  21.3/ 2.9k

       Id      User         Host/IP         DB         Time    Cmd    State Query                                        
       --      ----         -------         --       ----    ---    ----- ----------                                   
      781      root       localhost api_develo 28048   Sleep                                                       
      751       tic localhost:56454       pdk        4406    Sleep                                                       
     1084      root       localhost                        0       Query  init show full processlist 

BRs,
Geunsik Lim. 



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