Error writing in database during course restoring

by Павел Ломов.  

I want clone a course. So I created it's backup and tried to restore it as a new course.

I got error writing in database (see screenshot)

I enabled log (in config file)

$CFG->debug = 32767;
$CFG->debugdisplay = true;

Also according to recommendations https://docs.moodle.org/29/en/error/moodle/dmlwriteexception

I increased packet size to 100 Mb

Should I convert db files to Barracuda file format or the problem can be in something else?