[support] Druapal server fatal error: "MySQL server has gone away", but DB server is still up & accessible. Help troubleshooting?

[grantksupport at operamail.com]

unless I'm misinterpreting, it's -- as suspected -- a mariadb issue,
independent of drush version, and specific to MariaDB v10.0.11,

https://mariadb.atlassian.net/browse/MDEV-6340?focusedCommentId=52062&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-52062

working on it there.