In your posting:
https://moodle.org/mod/forum/discuss.php?d=468570#p1881098
---------backup error message-----------
Debug info: MySQLserver has gone away
-----------course import error message---------
Error writing to database
Got a packet bigger than 'max_allowed_packet' bytes
MySQL server has gone away
Our Moodle error message refers to 'max_allowed_packet', this is a mysql setting and moodle recommends minimum 4mb
max_input_vars' is a php setting and we are using the recommended value of 5000, our error message does not refer to this variable.
https://moodledev.io/general/releases/4.5
Server requirements
PHP setting max_input_vars must be >= 5000. For further details, see Environment - max input vars.
https://docs.moodle.org/500/en/Environment_-_max_input_vars?_gl=1*jpye6o*_ga*MTQ3OTQ2NDY4LjE3MDc3MzU2Mjk.*_ga_QWYJYEY9P5*czE3NTA3NzAwMDgkbzMwNSRnMSR0MTc1MDc3MDgyNyRqNTYkbDAkaDA.
From mysql client as root user:
mysql> show variables like 'max_allowed_packet';
Command line as root user:
php -i |grep max_input_vars
The two are related.
'SoS', Ken