MySQL server has gone away

[panterlo]

We are trying to address a problem that we have had with Postal since installed, we are running version 3.3.4 and get this in the logs when the Postal service has been idling for a while (e.g a few hours):

ERROR POST /api/v1/send/raw (500) event=request transaction=a67c2be378f7cb8bf2cc controller=LegacyAPI::SendController action=raw format=html method=POST path=/api/v1/send/raw request_id=1db3ed7f-4ae9-4378-846d-1a57d701fade ip_address=xxxxx status=500 db_runtime=5.543493270874023 exception_class=Mysql2::Error::ConnectionError exception_message=MySQL server has gone away exception_backtrace=/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:151:in _query'\n/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:151:in block in query'\n/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:150:in handle_interrupt'\n/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:150:in query'

Same also applies for the Postal Web GUI:

ERROR GET /org/tic (500) event=request transaction=d80d992c3761bd4aaf79 controller=ServersController action=index format=html method=GET path=/org/tic request_id=e42bbe8d-f248-4951-a741-7cea267e86c5 ip_address=xxxx status=500 db_runtime=3.1038198471069336 exception_class=ActionView::Template::Error exception_message=MySQL server has gone away exception_backtrace=/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:151:in _query'\n/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:151:in block in query'\n/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:150:in handle_interrupt'\n/usr/local/bundle/gems/mysql2-0.5.6/lib/mysql2/client.rb:150:in query'

We have set the attributes of MySQL correctly in regards to wait_timeout, connect_timeout etc but still this message appears a few times per day.

Any suggestion how to fix this ?

[willpower232]

This usually means your MySQL server has restarted for some reason, it might be worth checking the memory usage of it in case you are accidentally hitting some limits or perhaps it is fighting with another process to use the most memory.