Yesterday we received a report from a Chinese customer that he has a problem with MySQL and MSS. According to his report, after running for several minutes, MSS lost connection with his MySQL database and the error is “2006, MySQL server has gone away”.

Once connect to MySQL database, MSS will try to ping MySQL every 1.5 hours. By default, the interactive timer in MySQL server is 28800 seconds (8 hours). So we guess that the default timer values have been updated in MySQL. When MSS try to ping MySQL, the connection has gone, MSS failed to connect MySQL.

So we ask customer to check MySQL values with following command in MySQL database:

show variables like '%out%';

We care the result of ‘interactive_timeout’ and  ‘wait_timeout’ values. In such customer’s environment, these values have been changed to 1200 seconds.

We are not sure these values are changed default value by MySQL itself, or changed by some operators in such environment. If you have same problem, please take a check and  change these values to be bigger than 1.5 hours. We suggest you keep the default value which is 28800 seconds.

If we update above parameters, please restart MySQL and MSS in order to use new timer value for their connections.