Aim is to backup single subwiki , trash the subwiki and restore it fully and make the subwiki fully live via web portal.
dtests is a sub WIKI i created . This demo i am doing is to backup/restore just that database and the subwiki rather than restoring all other databases.
The restore process in that link talks about restoring mysql database so i think you pretty much nailed it down that the wiki descriptor points to a dtests DB, not to a dtests_new one.
The question rather should have been what must be done to see the sub wiki restored back? This is the info which i think is not very clear as i am following that same tech note you just send.
I tried the manual XAR import/export approach and that works but ideally, i would want to validate a full backup restore of a sub wiki in the proper way using mysql backups just in case the subwiki is deleted accidentally.