Issue with periodically lost connection to SQL server

[Vladislav Vlasov]

Hello.

I have an issue running DAGs in Composer - periodically (usually once in couple of days) a random task fails with the following error. Other time all works as expected.

{taskinstance.py:1148} ERROR - (_mysql_exceptions.OperationalError) (2006, "Lost connection to MySQL server at 'reading authorization packet', system error: 0"

After re-running failed task it completes normally.

Does anyone know what can be cause of this issue?

If it can be solved just by increasing timeout for SQL connections, is it any way to set it for the Composer? 

Thanks in advance.

[Simona S]

Hello Vladislav, 

We increased the parameter  Core\sql_alchemy_pool_recycle to 1800 from 570 but with regards to this variable Composer said that "Overrides have not been applied" and we continue to have the same error.

I hope someone can help us to address the problem.

Simona