Securing MySQL is always a challenge. There are general best practices that can be followed for securing your installation, but the more complex setup you have the more likely you are to face some issues which can be difficult to troubleshoot.
We’ve recently been working on a case (thanks Alok Pathak and Janos Ruszo for their major contribution to this case) where MySQL started becoming unavailable when threads activity was high, going beyond a threshold, but not always the same one.
During that time there were many logs like the following, and mysqld was becoming unresponsive for a few seconds.
2019-11-27T10:26:03.476282Z 7736563 [Note] Got an error writing communication packets 2019-11-27T10:26:03.476305Z 7736564 [Note] Got an error writing …[Read more]